Just FYI, you have zero chance of finding a Gen-4 under 50K without a bazillion miles on it, and honestly an 06 is pushing it too for a lower mile car, even a Vert. For the 40-50K range, you will be in the "average" category with regard to condition/miles. A super low mile perfect example will likely be at the high end or just over that, especially for special editions.
Also for what its worth, don't discredit the Vert until you drive one!
Under 50k for a gen 4? Yeah your right, but you can find gen 4 coupes/verts in "less desirable" colors all day for 55k. Even though most are sitting on a 58-62k asking price, i think they are changing hands right at the mid 50s on cars with mileage around 20k.
There are some people that are honestly drunk with some of the prices i've seen. Hell theres a blue/silver gen 3 coupe on autotrader for 60k right now. He'll be sitting on that one for a long time, unless its
worth the money to someone.
If you take a look at the sold listings on ebay you can get a good idea of what these cars change hands at, and ive seen some stupid deals over the last 2-3 months. There was a few 03-04 verts and mambas sold for 36, 37, 39, 42k, respectively. All look to be in great condition with around 10-20k miles. I saw a 06 blue stripe delete coupe with low mileage sell for 47k, the car had a set of iforged wheels, paxton, motons, full exhaust, and 5k+ in audio. The deals are out there from people that actually want to
sell them, and not just sit on them.
Last point to the OP; I wouldn't rule out convertibles. I was exactly like you in my search, i didn't want anything but a coupe--just because i couldnt get over how beautiful that rear 3/4 is. But in reality, there is something extremely special about being
out there in it, that you just miss out in the coupes. In fact after driving more and more convertibles i started liking them more and more and more, and now, the coupes feel slightly claustrophobic to me. I really wouldn't count one out until you've driven both.
My car started off in Sacramento to Oakland then container ship down the Pacific coast, through the Panama canal, to the Bahamas, Miami, New York, Halifax, across the Atlantic and finally ended up in Southampton. 
