Though you may not want a new UI, it may still pay to check out
DAoCMods, might find some info in their forums where the techno babble takes place. Also may be worth downloading a few mods and looking at the source code to see how others have modified successfully
You might also want to check out the
DAoC User Interface Editor. I just started messing with this the other day and it may be all you need. If you have questions about this one
there is a thread on the Vault forums dedicated to it.
And for even more fun reading
check out this document on the Camelot Herald.
I've been messing with modifying the chat window a little, and have not been successful as of yet adding a new window. I have seen where you can replace an existing window with a new title/command but I've not seen any UI's with an additional window. I like the idea of adding a new window, though I may just end up going with replacement of broadcast channel with one for battlegroups, because for me the broadcast channel is hardly ever used and battlegroup is frequently used.
Hope one of those links helps.
Maia