Re: "zenith of [cassettes]"?
I was thinking this morning of building the second frame with a 135OLN rear for 10spd but the 5mm was added to teh drive side so in effect assymetric. My reasoning being that is would help spoke tension and when I'm racing I'm using the top 2/3 of the cassette so thinking chain line would be better as well even allowing the no go area of big-big. The 9spd cassette less a cog on the 7spd hub sounds even better again.
Generally I think 10 was enough. It allowed the spread we wanted for racing with one tooth jumps just about the whole way. This is where the industry is kind of stuck in that racing sells the product to the majority of punters. In turn the punters have come to expect and demand something new every year so they can win teh arms race at the coffee shop. If they could change the perceptions of the punter away from racing equipment then we'd still have plenty of 9spd system being refined by teh manufacturers. IMO.
"Even my farts smell like steel!" -Diel