ever thought of building this yourself? It’s easier than you probably think, and it will make you proud of yourself. After all, this is a DIY place and people here are generally very helpful.
Because we’ve seen this many times before, just a simple word of warning: if you are interested in MIDIbox projects because you think you will end up cheaper than with a commercial solution (in your case e.g. a second-hand Tascam controller), you might have to re-think. Whereas the components might be cheap, things like large printed circuit boards in low quantities and a proper case/housing for the unit can become rather expensive.