Hey folks, in case anyone doesnt know already, couple years ago a 3 guys from the duke4 community (including Fox, a brazilian guy! ) managed to port Duke Nukem 64 Maps into Duke3d (the maps were not remade or anything, it was literal conversion from the 64's cardridge data)
http://duke64.duke4.net/
Handricks, creator of Duke3d's HDR texture packs was also on it.
Currently they are porting the PS1's exclusive Episode, Plug & Pray from Duke Nukem Total Meltdown.