It's gonna be tough as a lot - you will need to find someone with a shitload of space, and someone who needs 25 heads parts machines. For the most part, you only need one parts head from each manufacturer. I've have a parts head for each of the big three and they've lasted me 10 years with another 10 to go easy, and I'm fixing up a couple EMs from each company a year.
I'd suggest $50 a head (and taking offers) and sell backglasses and back doors (if any) separately.