I think the 5.10 issues are now resolved.
If ppm install http://theoryx5.uwinnipeg.ca/ppms/Net-SSH2.ppd will work for you, that would be the easiest way to get it. It's Net-SSH2-0.28 built against a static libssh2-1.2.1, so there's nothing else needed.
See how you go with that. (A slightly different ppm command will be needed if you switch back to 5.10.)