You are getting carried away in wanting absolute definitions with absolute rules of installation and then mixing and matching situations.

-If radials are not in contact with the ground, they are elevated

-If the antenna is not in close proximity to the ground it is elevated

*If an antenna and/or the radials are raised 1 inch above ground does the performance of the antenna dramatically change?   No.
 
*Do rules about the number of radials required dramatically change?  No.  It's not cut and dried that this '1 inch elevated antenna' now only requires two resonant radials per band, whereas 1 inch lower and it need 36 radials for optimum performance. 
 
It's relative.  The lower the antenna system, the more it is affected by earth. The higher it is the more it performs like an antenna system in free space.

Nicolo, have you gone to Scorpion's web site (or others for that matter) and looked at the install photos?  Those will give you some Ideas on how you can install the Scorpion or Hi-Q. Maybe the Scorpion 680s (S=shorty) would be a better than the 680. It's Length retracted: 28”, Extended: 36” 3”, much shorter than the 680.  There is a photo of a guy's SUV w/ the shorty on top.  And one on top of a Hummer.  These should give you some ideas.  You don't need to run a 6 foot stinger.  A shorter one will work or even better w/ a cap hat.  There is a way to mount it.  You just need to find it.
Good luck.

de wn2c  Rick

I have my Scorpion 680S mounted inside my aluminum truck cap and the performance is impressive to say the least.
I had it mounted out in the open through the summer and wanted to try it through the cap for the winter season. There is no doubt in my mind that the signal from my Icom 7000 travels further with the through the cap set-up. I've had many surprised contacts when they learn I'm operating from a truck. My antenna controller is a Better RF 7000 - works well for mobile use and I have a 48" rigid mast with a cap-hat.
Alan Applegate has posted three pictures of my truck on his site - http://www.k0bg.com/gallery2/main.php

Aside from all the engineering discussions...which I respect... I look at things from a simple point of view. I have always had good luck with Hi-Q although the bigger ones get a little pricey. A larger coil should have better Q and Charlie describes this on his website. He uses top of the line test equipment to check his findings. The military buys alot from him.The best thing I like about the Hi-Q is the physical length doesn't change with band changes since the coil is shorted internally, not externally. I've had reasonably good performance from my Hi-Q's in the past.

I have no experience with the Scorpion, but I hear they're good. However, they too are shorted externally and change length with tuning. It's just something I don't like.

73, Todd-KT0DD

KF7NUA,
you are right about the friction around here. I'm an electrical engineer and of course I work with many other electrical engineers. As such I work with open minded people who must quantify their statements. Feelings about circuits/antennas/etc. and hand waving are simply not part of the environment. Every design and every statement made must be backed up mathematically and proven to a dozen other engineers. We deal in numbers and not adjectives. So, to argue antennas with antenna amateurs (in every sense of the word) who do not have even a rudimentary grasp of antenna fundamentals, yet think they do - and who are close minded - is the real challenge. My time is better spent writing articles about antennas to educate those who are open to learning.   

Hi Nick,
I used a borrowed 20 meter hamstick style antenna on a triple magnet mount set atop my Buick Rendezvous for a trip from Texas to Illinois in the spring of 2012.  My rig was my FT-817 with a Heil headset/mic.  With 5 watts then, I worked Canary Island, Honduras and around the U.S.  It was not set up to be a DX dream nor did I QSO the entire trip.  I threw it in the car to try it out and see how I liked HF mobile.
So my results are subjective, and I have nothing to compare to.  It worked well for me, I was happy.  I liked it enough to buy an FT-857D which I will use in my car and boat as well.  I too am considering which antenna type to use now, and the Rendezvous has drawbacks for anything mounted on the bumper, the antenna being right next to the body for much of the antenna length.  I was going to just buy some hamsticks or hamstick style antennas since they worked well enough and could be interchanged from car to boat and given what I have read so far on several sites, I don't see a reason not to do that.  It's also at least $300 cheaper than a screwdriver antenna, and since I won't be mobile forever I don't see an immediate need to change bands on the fly.  Rest/pit stops serves well enough to swap out a hamstick.
That's my current leanings anyway, but still looking at the info because I won't be mobiling for a month or two at best.  This thread did leave me with the impression that there was a lot of discussion but not many answers to your question, so I thought I'd toss in my subjective review.  "The best antenna is the one that works for you" or something like that!   
73
Jerry

Anybody know anything about this?

http://www.steppir.com/

I saw the "teaser" ad for Steppir in the December CQ magazine and went to the website for information on their new portable antenna.  This seems like it could be a nice option for HOA-restricted hams like me who also work portable.  The question is: will it work?   What will it cost?  I guess we have to wait until Spring to know for sure.  I would be curious what the Antenna experts think.

73 de John, W7SAG

Hi Nick --

   My setup is pretty similar: an R7 mounted 5' above ground and an IC-706 running 100W. 40M is my favorite band. The ground conductivity is poor, but I'm on the top of a ridge that drops off steeply to the west, south and east, so that helps.

I installed my R7 a year ago and have worked 70-80 countries from the west coast on 40m. The Pacific, VK/ZL, JA are easy as is most of the near east. I also work EU long path in the winter mornings (they are beaming LP, whereas the R7 is "all path"). So it works pretty well for DX. I put up a 40M dipole at 35' a few months ago for comparison. The R7 and the low dipole are about the same for DX. A/B tests show little difference. Maybe the R7 is a bit better for the signals >5000 miles.  However for daytime local work and for US contacts at night, the dipole is *much* better by 2-3 S units, sometimes more.

Kevin
K6TOP