iGas has some interesting suggestions :
Altima Coupe = tiny. FWD makes winter driving a shade easier than RWD though. Cheaper if you find a dealer that doesn't rape you. Dealers around here sticker those things like they were Zs.
Maxima. Nice, large, drives well. Great motor just like the G, FWD though. Very good interior. A lot of bang for the buck if you're not a performance maniac.
Genesis Coupe. Smallish back seat / storage. Although the looks are definitely derivitive of the G, this is more of a Z competitor really. I don't think it quiet measures up, but it is a bargain.
370Z. Wow, really fun car, although many still dislike the exhaust note. This car is only done proper with the 6-speed manual of course. Solid, but like the Genesis coupe it's really only practical as a two-seater.
RX-8. Getting a bit long in the tooth, it's a great looking car that drives very well, but it has two glaring problems : lack of power (specifically torque), and horrendous fuel economy (worse than many V8s in daily driving). Arguably the most composed and forgiving RWD car in the price range, perhaps ever. Many cars approach their limits and feel great right before they decide to try to murder you. This car will start to break loose and give you a chance not only to recover, but to choose what you're going to do.
It's not my $ on the line, but I would definitely line up a series of test drives. Having had the opportunity to drive all of these (except a recent LGT), my $ would go to the G37 out of this list for a shared DD. If I could spare the scratch for a fun 2nd/weekender car, it would switch to the STI or 370Z easily.