I wonder how difficult it would be to adapt these to use with other vintage computers?

Not hard at all, considering it's just one of the cheap GBS-82xx boards in a nice box with an Amiga cable pre-attached.

Or you could just get one of the bare boards and save about $100.

Well, I have 2; A500 unexpanded, 512k CHIP RAM, with space on the mobo for another 512k, full ECS . And a nice A1200; no CPU accelerator, but with 8 Mb RAM extension, wireless PCMCIA network card and 1 Gb CF card, with an ATA-CF adapter, instead of the old and slow original 170 Mb HDD.
I also use WinUAE on my PC, with the CF card as the hard disk 😉
Is a lot more easier to move files. The CF card reader and wireless router make it very easy.

And I am still biting my fingers for not getting a 2000. FOR FREE!