I have occasionally thought about Ti bolts. My Cannondale is down to 17.8 lb and I'd be curious if I could get it to sub-17, without going to modern carbon fiber components. Ti bolts seem like the last resort though. Seems like drillium would come first. Reasoning being that replacing a given volume of steel with titanium would save less weight than replacing the same volume of aluminium with air.

Hmm, I just calculated that drilling 53 holes in the big chainring and 39 in the little chainring should save around 1.5 ounce. Gotta recheck that at home. EDIT: no, I'm wrong, that estimate is about 2X too high.