I have an 05 Specialized Roubaix comp. I am thinking of a new bike this year and I will be looking for just a frame set, since I just put a new 2012 SRAM Red group on the bike late last summer. Will probably want to get frame first, and build up bike using my current parts. Then, later down the road I will upgrade wheels, bar, stem, etc. I'm middle aged (47) and not getting any younger or more flexible so I definitely want to stay with a "relaxed" geo bike, at least a bike with a somewhat taller head tube. Also want top of the line carbon frame for sure; not considering any other frame material at this time. Light, stiff, fast, and fun!

Obvious choice would be another Roubaix, if that's what I do it will probably be an S-Works SL4. I'm also aware of the Trek Domane, and would definitely consider one; or an h2 or 3 fit Madone. Another bike I've become aware of that sounds interesting is the Focus Izalco Ergoride. It was highly rated in a magazine review I read, but I don't know if it will be up to par with an SL4 Roubaix, but it'd be quite a bit less $$. What about Cervelo? I heard or read somewhere that the R3 and R5 have taller head tube. What other similar bikes are out there that I can buy as frame set?