If you want to go back before velious UI, I got a classic one, or at least something close. It's Fabbe's UI, but one that actually works for project1999 lol. I edited the hell out of it.
Please do follow the Readme.txt instructions and remember to make it fullscreen so the UI borders and windows fit into place!
DOWNLOAD:
http://www.filefactory.com/file/b1d4...UI_classic.zip
SCREENSHOT:
Inventory
SCREENSHOT:
Spellbook