4.11 is not supported by Novell, correct.
XP does work and so does W2K. You just need to either use the Netware Client (ver 2.61 or later preferrably much newer) or the NDS Client from Microsoft.
Login scripts and everything work just fine.
Also, the best way to keep Novell happy is to continue to buy Upgrade protection. Cheap effective, about 1/3 the "upgrade costs" It also allows you to get Premium Support as an EDU for CHEAP.
Netware 4.11 was the first in amajor change the way Novell played with Windows. Just get a Client update and watch it work well.