I don't doubt you received a great deal. Where I'm coming from is: $2600 for aftermarket rods; $1200 aftermarket pistons; $1000 for an aftermarket cam (kinda needed for a big single is you like to get the most out of it for DD use, but not a must); machine work upwards of $2500 and that includes key and assembly, and that price comes from a reputable shop with good experience. That doesn't include valve springs or any of the extra stuff that you mentioned. Nor does it include an extra engine, or at least a block, unless you wanna ride your bike or borrow Mom's car while yours is out of the truck getting built.
I'm sure that I could cut some costs, I'm simply quoting some prices that I e been given and what I see on some of the guy's sites that support this forum. If that's their price, it is what it is. In doing the homework it adds up quick, everybody knows that and Tony has valid points. I think most, of not all, of the supporters would help a guy out to cut costs when they are able, but it does cost to play and everyone has bills, including shops.