Well, it's still listed on Eyetechs web page, but I wouldn't recommend saving £105.75 just to get a cheaper model. The price difference between G3-SE and G3-XE is 25%, and that's about how much faster the G3-XE is, and it's got a CPU board you can replace with single (already out since December) or dual (been tested and will start shipping soon) G4. Please show me a better example of more bang for the buck, eh? It's also got the sound codec onboard, so no need to look around for a riser card... And the ATX backplane layout is dead standard, so no need to cut your own... Hmm, is there ANY drawbacks? Don't think so.
In short: Go for the G3-XE, it's shipping now...