Not sure what the heck Stuart was talking about there claiming the satellite was "designed for SD". That's like saying my car was designed for to be driven on the right side, and couldn't be used in the UK.
Transponders have a limit to their bit rate, but they can be bonded together (bandwidth added between them) if you wanted to carry something very high bandwidth like 8K. There's nothing stopping them doing that with 101, well other than that being a waste of "prime real estate" and the fact there are no 8K channels...
Of course, you can tweak the bit rate to anything you like, up to the Shannon limit (not sure what that is for Ku) They could make a transponder at 101 carry 100 Mbps which would be more than enough for an 8K channel. Of course you'd have so little signal margin a few little puffy clouds might be enough to give you "rain fade"!