The second circuit is almost identical to SI Prog, the serial programming adapter suggested for PonyProg. I guess, there will be some 100k working out there. You possibly may want to add protection for the MISO line, but apart from this point, it serves the purpose, I think.
I know, by the way, several professional instruments, that are using 0 to 5V CMOS level for RS232 TxD. It's in fact ignoring the RS232 specification, but apparently not causing problems in reliable operation. The cable length is mostly short, of course.