I have a HH LH bow, it is 65lb at 27".  I am a RH shooter, just wondering if anybody has flipped the bow over and cut a new shelf in it to make a RH bow out of it?  If a person could do this it would open up a lot of longbows to be more useful.

I've done this before. I don't have any pics of the bow but what you explained is exactly what I did.  That was bow #3 for me at the time and I traced on my riser template backwards and ended up cutting the shelf on the wrong side.  This works best for a straight or dished grip.  Good luck.

You can leave it rightside up, glue a leather rest on the off side, and have a perfectly fine LH bow that will need slightly softer spined arrows to shoot well.

I did the same thing as bjansen, realized as soon as I finished.  I glued the sightwindow cutout back in place, flipped and re cut.  Not the prettiest but sure shot and held up fine. I could never bring myself to do it to a HH bow.

I explored this idea with Craig at Hill Archery a couple of years ago.  He was against the idea as he felt that it weakened the riser and left the bow vulnerable to breakage from sideways shock, like if you bumped it into a tree or something.   His recommendation was what No-sage said...  just slip a thin leather rest into the wrap on the off side and shoot it off of your hand.   Takes a lighter spine, but works very well.  I actually build about a third of my bows with no shelf at all so that they can be shot off the hand from either side.

Here's a pic of what I'm talking about:



The leather "rest" doesn't need to be as deep as a shelf.  All it is is a reference for arrow placement, and the leather piece also provides a swelling that provides muscle memory for your hand placement.