Belly (oil pan) skid? We've done some custom stuff on our buggies that integrates the engine crossmember so it definitely works, we use bolt flanges of some sort to bolt to the engine and t-case x-members. I don't see integrating a bolt on system anytime soon due to variations in exhaust systems, crossmember locations, etc, but it would be pretty simple to do on a custom basis.
Aftermarket oilpans? Shouldn't be a problem within reason. Typically the deep sump pans use a stock profile under the front and just add a deeper sump. I ran a deep pan on my 383 that the original crossmember was built around then we dropped the big block in with a moroso 7qt. Obviously neither was an issue.
LS1? We'll sell you the brackets to build your own? You're going to have custom motor mounts and a much different pan profile so all bets are off with that one. It might work but then again it might not.