- Cube 2;
- id Tech 4 (or the upcoming Doom3 BFG source);
- an older id Tech engine, e.g. ioquake3 that just got a new advanced renderer;
- Retribution Engine;
- Torque (apparently Direct 3D only, however).
Why?
- use an engine that is actively developed by others so Eduke32 developers can concentrate in other areas;
- use a 100% free (as in FSF), DFSG compatible engine, hopefully to make Eduke32 more popular in Linux and open source communities (and to have it natively included in Debian/Ubuntu/your distribution);
- just for fun (or craziness, since it may too difficult to make any sense? ).