The thing is, about the T5-76, why is the external UBS port still offset to the right of the keybed? This adds quite a few extra inches to the length, and one would have thought that the ONLY extra stuff added to a T5-61 was merely the keybed. So leaving the innards in the same position that they are for the 61 would place the USB port above the last few notes, and the end plate could come in some 3-4 inches.

But they moved it over so it is symmetrical with the 61... That's going to make for a tight fit in many 76 cases, or you might have to use one for an 88.