Outside of a full custom, are there any semi drop in's that I can semi inlet & finish?

MPI would probably fill that need. I have two of their Kevlar stocks. In spite of lots of hard use, they work great. E

An option if you want wood or laminate is Richards Microfit. I've heard mixed reviews, but my sample of one was a fine, enjoyable project for my wife's 721.

Richard's Micro-Fit would be the budget option. I'm not a huge fan of Richard's stocks, as they require more work than I prefer to put into a stock.

Wenig would be the expensive option. You're likely to pay more for a Wenig stock than you would pay for a new Ruger 77 RSI.