Dnj, when it comes to controller keyboards (keyboards without effects and instruments), I prefer the Roland keyboards, namely the A37. I have tried some of the Roland/Edirol as well (don't remember the model numbers) and they will get the job done. The best is to test them with the module or computer with which you are going to use such instruments.

DNJ you are planning the right approach. Your customers are going to be impressed on how such a minimalist approach sounds so good.