Yamaha MO8 could be a great investment, but alas the Yamaha piano sound is a bit weak - too bright and "steely".
But I would say that getting a stage piano wouldn't be a bad option either. Roland RD 300-SX is _awesome_ for its price. If you want more, with some extra you can get the RD 700-SX, which is more like a total stage workhorse easily competing with workstation solutions due its two SRX expansion slots.