Going up from the sump...

[Output Flange]

This could go in here or in BMW General, but given I know what I want the answer to be, I'll stick it in here

You've got the sump from an E34 M50 engine. You've got to stick with that - no alternative.

However, above that is pretty much free. So, you could stick an M52 on top.

Can someone confirm then that you could also stick either flavour of S50 on top (albeit with the M50 pickup), and perhaps an S54? Any others I've not thought of?

[warsteiner///M3]

yes,
s50 (3.0 and 3.2) and s54 blocks will both fit on top of the e34 m50 sump....with the e34 m50 pick up