George is dead on there. Most of them do only record 2 tracks. You know there is one good board out there with 88 weighted keys and full 16 track recording. Have you considered the Korg Triton LE. I'm pretty sure that model has a better acoustic sample than the other LE's. I think the 88 model has a 16mb piano. You also could consider something like a Motif ES with 88 keys, or even a Roland Fantom with 88 keys. These boards are portable. You can go much less in the weight, but like George said those models typically have 2 track recorders.

Squeak