yikes. Exactly how deep are your pockets?
I think the closest you're going to get is an engine that has been rebuilt by professionals with exacting standards. Someone like Metric Mechanic. It's going to cost you a pretty penny, but you pretty much have a "new" engine. Most of those guys have warranties as well.
Hope this helps.
'86 325es (TURTL3): PJ peetsa hawler
'87 535is (BADWATER): almost done... really.
'86 325e (GRN HLL): DD/show/rocket
'04 x3 3.0i: Wife's Bimmer (manual, woot!) My BMW Blog