I bought an M-10 for my current project sled, then afterwards I found the skid that I really wanted (polaris 144" dpr skid). So I have this M-10 that I don't really need. It's about a '97 model. It's light purple (very common skid sold around that time). It's a 136" right now, but you can pull off the rail extensions to turn it into a 121". The top end is set up for wide-body Yamaha (it was in a '94 Vmax, approx. 17.5" wide tunnel).
$850 plus shipping for the M-10.

I also have a Polaris wedge chassis mount kit for the M-10. It's unused. I believe it will also work for GenII chassis.
$175 for the mount kit.

PM or email PerformanceX@usa.com

some pics.
M-10 has Fox shocks.
Mount kit is missing template, but you don't really need it, as you can use the tunnel mount plates as a template just as well.

I sold the rail extensions, so the M-10 is now merely a 121".