There is/was at least one on the forum. He sent me a nice little summary in a PM but I seem to have deleted it. Basically a longer stock screw, long enough to put through the weaver rail and hold it to the stock while also holding the rifle in the stock. No drilling. Doesn't seem like the strongest way to hold a bipod in place (to much potential movement/leverage on the threads in the front barrel band). But, other than milling the stock , I couldn't think of much else.
I went a little simpler route and simply bolted through the weaver rail, with a couple jam nuts on the back, and left enough bolt to stick out the back about an inch. Covered that bolt with a tube that fit into the access hole for the stock screw then filled it (the tube attached to the weaver rail, not the stock) with epoxy and let it dry then wrapped it in grip tape until it was just barely a snug slip in fit to the hole in the stock for the stock bolt. This left the original stock bolt untouched. Certainly nothing you could carry around attached to the rifle but it worked fine shooting from my bench and was basically something that would just drop out when I picked the piffle up. Mine is gone.... no pics sorry. Careful not to split the stock!!
Edited for a little clarity....