arbitrary keyboard mapping

You can use .kbm in Scala and generate a new .scl with that mapping if you want.

I've just tried creating a tuning file with Scala and it was pretty simple (for basic use at least). First, define the scale degrees and their relationship to each other (intervals in cents, or put in frequency for each degree in hz if you want), you only need to do this for one octave and it will automatically extrapolate (your octave can also be bigger than 1200 cents). You can also control the range and how exactly it will extrapolate if you want. This can be done in the edit menu so you don't really need to write actual codes, though more advanced scales might need coding. Then, you map those scale degrees to the keyboard in any order you want with the mapping menu. You can check your result with an onscreen keyboard in the play menu. Then, you just save the thing into .scl or other formats.