"have not found a stealth antenna that appears to out perform a vertical - low radiation angle signal and S/N ratio. Please let me know if I have missed anything in that area. "
Keep reading and start experimenting.
Sometimes you will find strange things (and some not so strange things) about signal-to-noise ratio especially.
I agree with the others that aside from maybe adding some more radials, a 22.5 foot flagpole with a tuner at the base is a pretty good stealth transmitting antenna.
But if you're having *artificial* noise problems, learning to get rid of them and design antenna installations to minimize them is one of the keys to a good DXing antenna farm.
I do pretty well with DX but I always have detectable artificial noise, probably sometimes keeping me from really hearing a DX station clearly.
So there's probably always something I could be doing to hear better. At the moment, I've decided I hear "well enough" because it would be a real full time job to hunt down and eliminate all suburban noise sources, if it even were possible. But it's just a slow development of noise troubleshooting and antenna learning skills. The best S/N ratio antenna for you is going to be the one that picks up the least electrical noise while picking up the most DX signals. That may sound a little stupid and trivial, but the only way you're going to find it is if you try something.
Don't discount some of the techniques some people use on the low bands. I use a flag on 160m,80m, 40m and 30m (with maybe slightly less performance on the top two)http://www.n3ox.net/projects/flag
But I actually built a little high band flag for a special purpose, and there's no reason it wouldn't work up there. Arrays of even smaller flag antennas might give some good results. You can scale it down to something like 1.5 x 3 feet, turn it horizontally, mount it on a rotator on the roof, say it's your HDTV antenna, and be VERY VERY careful about common mode noise pickup, use a good preamp, and it will *hear* as well as if you had a two element yagi on your roof. Wouldn't transmit worth a damn, but that's what your vertical is good for.
Arrays of really small verticals around the yard for receiving could be disguised as all sorts of stuff.
You could scale down W8JI's 160m eight circle to work on 20m and 17m with probably excellent receiving results:http://www.w8ji.com/w8ji_rx_ants.htm
These are *extreme* measures of course.
Otherwise, I think you're in good shape and I would not worry much about the station at that point. Just go DXing. When the bands are poor, you'll hear every bleep, bloop and buzzzz of everyone's electronic crap, but as you get confident in the fact you can work DX and as you find when the good openings are, you'll spend more time DXing and less time listening to junk noise.
I would at least make sure your own nose is clean as far as your artificial noise problems. If you can just unplug an air purifier or put some chokes on the TV for the kids' room or something, you'll be a much happier camper.
Back when I was N3UMH, starting out and living in my parents' place in high school, I had a little tower and tribander. Every time I would point that thing toward Asia on 15m I'd get awful noise. At some point it dawned on me that pointing to Asia was POINTING RIGHT AT THE HOUSE, and furthermore I realized that my bedroom shack was the closest thing to the heading I had the antenna on.
I started unplugging stuff, and when I unplugged the switched off TV, *poof,* noise goes away.
Make sure you don't have any of that and then go find some DX.