I'll keep my 61 note Tyros 2. The 76 key thing is not an issue for me, but I'm not buying any more arangers again until either my PA80 or T2 break down. For the small amount of live work I do, either or both are more than adequate.
I don't like styles much at all for studio work. I like Korg's and Roland's better than Yamaha, but in the end none of them allow enough diversity for me to incorporate much or any of them into a studio song. I tried making styles before, even made a few that I liked, but in the end, if I'm creating a style for a specific song idea, I find it to be easier and less work to simply play all the parts in real time, or in the case of drums, sequence them from software like Jamstix or the older versions of Jammer Pro ( version 4 ).
If and when an arranger comes that allows for some real diversity in their styles, in real time, ala a Karma type effect or using a concept like Band in A Box uses where the styles can play different parts randomly or automatically, then I'll consider another arranger purchase. I'm tending to doubt, based what appears to be the target markets, that this will ever happen. I like the BIAB concept, but I've always felt that the best styles are geared towards Jazz genres.. some of them actually can sound fairly good. I've never cared much for their styles in any other genre.