The Beetle still has it's original block and has done a whopping 429,000km judging from the few fragments of history I can find. I'd say the engine has been rebuilt as it's quite spritely but the gearbox is tired.
The Corona has done 134,000km, the engine is not original as the old one did not like the Australian climate.

The MR2 has 172,000 miles on it, but the engine is not original.
Traveller - no idea until I find which box the speedo is in. But the engine is original.
Cheers,
Brett.