Currently, there is only one arranger keyboard with 76 keys on the market, Generalmusic SK760 (also an 88-key model SK880). Roland G1000 has been discontinued, but you may be able to find the remaining stock in the stores for about $1300, which is probably as much bang for the buck as you are going to get. SK760 has more features than G1000, such as sampling, editable voices, vocal harmonizer option, built-in hard drive(?), but the Roland sounds very good (I own one).

There are rumours about a new 76-key proffessional board from Yamaha, though it is not out yet. Feature-wise, it should be comparable to SK760, though some people like Yamaha styles a bit less.

Of course, there are also electric pianos like Yamaha's Clavinova, Roland KR series, Technics and Korg CI8600/9600, but these are much more expensive, and not at all portable, as they include a cabinet and speakers.

Regards