For just $1199 on eBay, you could purchase the Nintendo N64DD and N64 development dynamic drive dev. The seller notes that the N64 Developmental Cart features a partial build of a game from the previous owner. Auction page. Click here for first picture in gallery.
I should also printout the N64 has extra circuits boards I’m selling this I have not tested this. I’m including a unofficial Data CD, that would be useful for someone just starting out and wanted to do some programming with this.