IMO the distinction between repro/bootleg just comes down to the intentions of the makers. If they're out to turn a profit, it's a bootleg. If they only charge for parts and labour, because they want to provide a service to people who want to play otherwise inaccessible games on real hardware, I'd consider that a repro. The quality of the product doesn't matter - bootlegs can be hand-assembled and repros can be professionally produced.