I would buy a carrying case for my Legend and my 82-key. Bonus points for matching colors but all black would be perfectly fine.
I have been searching online for the last couple weeks trying to find a perfect sized laptop case/sleeve for my 82-key board, and the closest I have found is a
MacBook case that is 12.78 x 8.92 x 1.08 inches
and one that is 1.1 x 12.8 x 8.9’’ . It seems that most of the laptop cases are too square, they have the correct length but have a width too big (10 inches or so). I haven't found any cases for full sized keyboards yet (although I really haven't tried too hard).
I would think something like Neoprene or another waterproof or water resistant material for the outside, and perhaps velour or plush inside. Handles for the case aren't that important but might be handy if just carrying a laptop in a sleeve which has handles and the keyboard in a sleeve.