I had 3 Honda RC-51`s 2001, 2002 and 2003, a 2001 Honda 929, a 2004 CBR1000RR.
I currently have a 2008 CBR1000RR, a 2008 1098S and a 2008 HyperMotard-S.
Of all these bikes the 1098S is by far the easiest to hang off off. Yes the frames are narrow on a V-Twin, but ergonomic setup also plays a big part. Clips on`s need to be in at comfortable position as well as foot peg location. My 2008 Honda is wide between the legs, but I find the foot pegs too high to get a comfortable hang off position. My knee`s are to high and I can`t get a good grip on the tank like I can with the 1098S. I was thinking a rear set would help and maybe some traction pads could finish the setup.
Of all my recent bikes, I think the RC-51 was the hardest bike to lean off of. It also has a lot to do with suspension setup. The 51`s where like riding a plank with a stiff/harsh (stock) suspension. I never changed it out, but I have tested the 1098 with stock setup and found it to be just as easy to hang off as my 1098S.
For me the bottom line is Ergo`s and Suspension. ..