I think it would take hours of inletting for the 77/22 in a 10/22 RSI stock, if it even fit. They are completely different actions, and the 77/22 is quite a bit longer.
some months ago I had a communication with Lipsey's and referenced a 77/22 Int. the response was....."watch for something in 2012" so I am assuming that Lipsey's will have a special run in 2012.
personally, I am looking forward to it. always liked my 77 rsis and a 22 to match would be great.