I've seen guys make their own plates on Cummins swaps.
My current plan is to get a DT flywheel, and just machine it down to the same size as a Cummins flywheel, then drill it so a Cummins pressure plate bolts on to it. On a Cummins swap, the whole clutch out of the Cummins is used - just requires a custom pilot bearing.The Cummins clutch is proven to fit in the ZF5 bellhousing, and there's more options for clutces if I use Cummins parts.
I can use my SAE2 adapter to drill the bolt pattern in the adapter plate for the block, then I need a spare ZF5 to use as a template for drilling the ZF5 bolt pattern into the adapter. After all of that, I'll hang a dial indicator off of the crank flange, bolt the whole thing together, get the crank centered on the input shaft of the transmission, and drill and install the dowels for the tranny.
Then I just have to make the clutch fit and work, and find somewhere to put the starter; it has to go on the driver's side of the engine.