I did look into this myself for the same reason as I have a bad knee.
Nobody does as far as I know a 790 version of lowered footpegs although MFW do some for the 690 and I am pretty sure from the foot peg dimensions they would probably fit the 790.
Vario and Replacement Footpegs
But there would probably be touchdowns regularly when cornering, and the 790 likes to corner.
I opted for the higher seat (+an air hawk)and bar risers and so far all good, no real knee discomfort issues and I have done a few full day rides.
Nobody does as far as I know a 790 version of lowered footpegs although MFW do some for the 690 and I am pretty sure from the foot peg dimensions they would probably fit the 790.
Vario and Replacement Footpegs
But there would probably be touchdowns regularly when cornering, and the 790 likes to corner.
I opted for the higher seat (+an air hawk)and bar risers and so far all good, no real knee discomfort issues and I have done a few full day rides.