Question : Win Svr 2003 w/ NT 4

If you I were to run Windows Server 2003 with Windows NT 4, BDCs use mixed-mode, set the compatibility option, run DCPROMO, or run the UP2K option on the BDCs?

Answer : Win Svr 2003 w/ NT 4

Do you have a particular goal or requirement?  

You can mixed Win 2k, Win 2003 and Win NT4 if you need to.