I had an On One 45650b which rode very well in my opinion. I purchased a second hand Vitus Escarpe frame on Pinkbike and transferred all the parts.
Only things i needed were adaptors for the rear hub and a different sized seatpost. The other thing was the rear brake hose wasnt long enough for the new frame.
What i liked about the 135mm travel is that it feels closer to a hardtail than i imagine a longer travel frame would. Although i havent ridden any of the current crop of 150/160mm Trail frames.
Transferring the parts was painless and didnt take long. First ride out i was amazed the difference it made and the extra speed i could hit things at. The bike is also really quiet which is nice. Just the noise of tyres, freewheel and me struggling to breathe.
The On One
The Escarpe