jmtd → hardware → mac mini g4
A compact, quiet machine, well suited as a backup/NAS server.
I believe the Linux kernel (and therefore Debian) no longer support 32-bit SPARC systems, so this is an architectural dead-end.
Sadly, suspend won't work out-of-the-box due to issue waking up the graphics chip. It might be possible to hack the kernel to turn on suspend, if you can ensure that none of the graphics stuff is initialised.