Solution found!
There is an unsupported bypass someone way back when found.
Seen here: https://web.archive.org/web/20050307001059/http://www.zvenigorod.ru/solaris8x86/p4trick.htm
Michal from www.os2museum.com found me a similar workaround.
Now I just need to find a way of getting video card drivers working. I've found Linux drivers for Intel 845G, but well...I'm still getting used to this Solaris\Unix\Linux\etc stuff.
Thanks again for all the help & input.
I'm not a Gentoo user, but their documentation is pretty top-rate, including how to net boot the machines.
http://www.gentoo.org/doc/en/gentoo-sparc-faq.xml
You should really get some disks in it, even if they're just 18GB 7200s. I'd load Debian, but that's just me.
K. How about this for USB -> RJ45 and RJ45 -> Modular DB25?
Cheaper anyway ...