I recently got an Arturia MiniLab MkII 25 MIDI controller. While going through a tutorials for Reaper, I I realized I wanted the keyboard to be more accessible. After contemplating, I designed this. I took a guess at an angle (30 degrees). At first blush I'm incredibly happy with it. It should work with most of the slimmer MIDI controllers, etc. and possibly for many other applications.

Print two "base.stl" and one of each of the others.

The orientation should be correct as distributed so you only need supports for "middle.stl".

If are less concerned with stability, you might be able to get away with one "base.stl". one "left.stl", and one "right.stl". It still works this way, but if you press hard on the left or right sides it may fall over. As designed (with two "base" and the "middle", it is quite stable).