XMenFilms.net is reporting a rumor that the characters both Omega Red and Gaunlet will also appear in cameo roles for X-Men 3. The site says:
The X3 cast is ever-expanding with cameos from the X-MEN comics, and now XMF can exclusively reveal two more cameos that you’ll see on the big screen, come May 26th 2006! We back this statement with 100% confidence, and have seen visual proof, so there are no doubts.
To know which scene they’re likely to appear in, visit the link above.