I've used a Fusion frame for one build. Tolerances are tight. Now if you want, I have a complete kit ("original" SA frame, Colt Commercial slide, (possible Colt) barrel, and all the fixin's) to assemble a complete mil spec 1911a1. It has been aluminum blasted for refinishing. You would need to use a lapping compound for the slide to move smoothly on frame. I will also thrown in a can of Gun-Kote (gray parkerize color). Make me an offer (I have approx $500.00 in it). If I like your offer, I can send it to an FFL dealer in your area.
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Life Member NRA
Life Member NAHC
Former President of the ECPT (Eifel Combat Pistol Team)