You've already gotten the two main suggestions for the conversion. If you get the taildragger conversion from Sig the main gear will be mounted in the wings. This works fine but is not as sturdy as the suggestion of mounting a good aluminum gear directly to the fuse. I would suggest that either way you purchase a good after-market tailwheel and build it right in as you frame up the fuselage.

A-hogs are great planes and make excellent taildraggers.