IIRC…
1. Started as ss only frame with horizontal track ends and canti mounts, in 853.
2. 2nd generation was 'DN6' Chromoly
3. after a little while it became available with vertical dropouts (2001, my 1st)
4. and then Ti with vertical dropouts or EBB, as limited numbers
5. Then a DN6 EBB. I got on great with mine, and nearly regret selling it even after I'd crashed and bent it.
6. then things get more hazey as the 456 is launched (04/05 at a guess).
7. But then inbred become uprated to longer forks and the afore mentioned sliding drops – one frame for gears or SS. Other changes: larger diameter top tube and bridgeless chainstays. Heavier too, and IMHO, just not as good to ride. 2006?
8. An 853 version of this frame, 07? Summer season frames might have been started about this time too.
9. Then to save costs, the frames use a disc compatible track end for gears or ss. Prices became lower than ever. 07 too I think.
10. Think it's roughly the same today, but with more colours?
No inbred is very light, but I prefer the skinnier ones, and I have never had much trouble with rust…