Sorry to reply to this old thread, but I didn't want to open a new one just for this.
The W2K IPX works great for Diablo 1 (Version 1.09).
The current Wine version (0.9.25) requires a patch to make Diablo work, see bug 2082
in the Wine bugtracker. This patch seems to be a bad hack, the bug report has been around for over a year without getting fixed properly. If you're interested in getting this fixed, register at their bugtracker and vote for the bug (or if you're a programmer, see if you can help out somehow).
The main problem is the game menu, which is just a black screen (without the patch) and is usable but has many graphical glitches with the patch.
As for IPX support and playing in the local network. It works. You have to enable IPX in your kernel, install ipx-utils (hopefully provided by your distro), configure and add the init.d/ipx script to your startup scripts.
When selecting LAN/IPX in Diablo menu, you may then get a message 'could not initialize connection method'. This problem may arise if Wine was not compiled with IPX support (check the wine ./configure output, it should say something along the lines of 'checking for ipx or whatever ... yes). It may also be a permission problem (if you dare, start wine as root and see if this works).
Unfortunately I'm not sure which groups your wine user has to be in, or which device / which permissions have to be changed to make it work for normal users. Wether it will work out of the box for you or not depends on the way your distro manages permissions.