Any bar can have a winch mounted to it but it will depend on what sort of bar it is as to how hard it will be.
Steel bars are usually relatively easy and often have the spot ready to mount but if you've got an alloy bar you'll need to modify things and that may make it too expensive to warrant doing it.
I have no idea who's done it but I'm sure there is a few threads on this forum that show alloy bars and winches and there is definitely threads for steel bars and winches.
