I do wish PAR would add a wingnut ground post on their end-fed antennas. I know they omit it for rhetorical reasons, but even an end-fed wire benefits from a real RF ground... it can be a bunch of very short radials. My 40m antenna is an end-fed-half-wave vertical and I feed it against my radial system just like on any other band. No reason not to if you have the radials available.
The nice thing about an end fed half wave, though, is that the capacitance of the coax shield and rig case to ground usually provide enough of a ground return for the antenna to work properly and reasonably efficiently.... lack of a ground radial system doesn't totally destroy the effectiveness of an end fed half wave like it would a quarter wave.
All in all, I think some Par End-Fedz or equivalent antennas would be a good choice, and I wouldn't worry about feedline decoupling too much when running 10W. It just won't cause you that much of a problem. If you're out in a portable situation and the feedline is on the ground, it just acts as your ground system.... yeah, it has current on it, but so would a set of radials.
If you use it from your dorm, you might try grounding the coax shield to some handy bit of metal or a resonant radial to spread out the current a bit... but I don't think you'll have too much problem with RF in the room just because you're not running a lot of watts.
I think the biggest problem in the dorm would be the other way around... noise coupling onto the antenna because the feedline is poorly decoupled from the antenna... but the ONLY WAY to successfully decouple the feedline from a PAR End-Fedz is to rig up a good RF ground connected to the shield of the SO-239 connector at the antenna... would be easier if they gave a ground connector.
I wonder if they could sneak a single green PowerPole recessed in the housing without anyone freaking out that the antenna all of a sudden had a place to hook up a ground ;-)
73
Dan