The non-traditional swap is a MB W120 DOHC Aluminium V-12. The trans will be T-56, either backing the block or from a C5. Hydraulic clutch (probably a Center force dual friction) will simplify linkage issues. Probably too much trouble to adapt the AMG 6-speed to the V-12.

I'm going to draw the line at chassis fab, so I doubt I'll go to the trouble to adapt the C5 3rd.

The bell-housing and the flywheel will both be custom made, but my preference is to use an existing ring gear for the flywheel. Plentiful options for ring gears are mostly US-made.