I wouldn't normally post about such applications, but the new EvoX is now supposedly compatible with Gentoox, even if IGR is left enabled:

EvolutionX Build 3935
>> EvolutionX Is a alternative dashboard for the xbox
Whats New:
- Debug TSR works now (except on net games)
- FTP bugs corrected
- SymbolicLink always maps D: to DVD now
- IGR problems with Gentoox, Phoenix BIOS loader and Xromwell is fixed now.
- Many more minor things

Let me know if it works via the forum.