I drove down to see Kevin Brooks today. He took a look at the crank, cam, cylinders and pistons from the R50 and deemed them perfectly acceptable for re-use. I had planned on getting the cam re-plated and ground due to the small amount of pitting but Kevin said that it was best to leave it be as those pits will work as tiny oil reservoirs, protecting the lifters. That's fine by me as it means even less money spent. Kevin said that I just need to hone the cylinders and install new rings and I'm good to go. He said that one of the pistons had run extremely hot at one point which resulted in a bit of melting on one edge, but that it was still perfectly serviceable.
Kevin was also kind enough to make use of his oven (best shop accessory ever) and hydraulic press to press the cam gear off for me. I left the crank with him so he could replace the small end bushing on one of the rods.
Now I get to sit down and make a shopping list for all the little pieces that get replaced in the rebuild. Thanks to some advice from Kevin that'll be a little cheaper than I anticipated.