if you're going to build a midibox64 anyway and need just a really good keyboard, i'd recommend an ensoniq mirage, or a casio VZ-1. the mirage for example has weighted keys , they're all very sturdy and way better than any of the crap you can buy today, especially for the price. such keyboards usually always go for lower than 200€ on ebay. also a good keyboard i had was the ensoniq EPS. good sampler too, btw!