A "dedicated unlocker" could be concocted on a breadboard within perhaps a hour, if you have all the components at hand. It's just to set proper logic levels on a bunch of pins, provide +12V (possibly through a resistor - it draws only "logic" amount of current) on /EA and then a pulse on ALE. Maybe it needs some sequencing but I doubt it's more than what can be done with a simple mechanical switch. The pulse on ALE might need to be provided from a clean source, but for starter I would use a plain pushbutton. If the clock fuse is set to non-crystal you might need to provide an external oscillator, too, but then you'd need that also for ISP anyway. Yes you might fry your chip in the process, but if I understood it correctly, it was a freebie and you don't really need it.

I know that from economical point of view it is a nonsense, but we are not talking economics here, do we.

Isn't *this* what hobby is all about?

JW