E-MU PK-6 Proteus Keys.
Roland RS-5 or XP 30.
Yamaha Motif 6.
Korg Triton Le
They all are very good synth with tons of sounds and only 61 keys to be on the top of the SX Kn6500. It's your choice, price range it's pretty much from $899 and up.Hope this selection will help narrow down your options. Good luck with your search!

Maximo