You may want to have a quick read through here.
Think a USE Ti with a shim and Ti bolts would do it.
Or another make of Ti modified with Ti bolts etc might just nip under the 200g. Cutting it down to 290g will help quite a bit there
Not many of these are not retro. (see tune/kcnc and most things sub 200g ) http://www.retrobike.co.uk/forum/viewto ... c&start=15