I guess the solution would be to crack the engine open and try to fit another 5th gear from a bigger model? (what bigger model??)
Since you have 1000, i can't think of a bigger brother of the same engine which might have slightly different gearing...
changing wheel...: again, find one which is bigger, but plug'n'play with the shaftdrive... I swapped wheels in my previous bikes many times so I appreciate the ballpark what the chaindrive gives me. Shaft is definitely better in performance, maintenance though.
transmissions... CVT? I have never heard of big enough which could handle the GS1000, but who knows... cutting it up and putting it in however makes it an absolute no go for me, specially if we consider the loss of energy in the transmission due to slippage...
but theoretically I guess, this is what you thought of...?
