In addition, most "road" bikes are engineered for racers, who (one G. Hincapie excepted) are pretty diminutive and lightweight people. If you're over about 6'3" and 210 lbs, it's doubtful that you should be riding a modern all-carbon frame. They're just not engineered for you. And the frame is just the tip of the iceberg. Equipment, shoes, clothing, it's all a bit of a struggle for us "Clydesdales" (male) or "Athenas" (female). (I don't know the origins of these terms, but if you know or are willing to speculate, please comment!)
The main Internet / mail order bike guys, Performance / Nashbar, tend to be places that say, "If we've got it, it's in stock!" This means that finding outsized clothing or shoes is usually a big time-waster. Nashbar used to have a great feature on their website that would display only shoes in the size you specified, but for some reason they've given that up.
I thought I'd use a posting to share some of my finds with other tall and/or big folks. So this post will be about some vendors who deal in clothing and equipment for tall persons:
REI: This venerable outdoor gear purveyor sells a decent collection of tall sizes active wear and outerwear. The cold-weather tunic I now use comes from them. They don't however stock large-size cycling shoes. Just search for "tall" on their site to see what they've got. Check out their "outlet store", too.
LL Bean: Similar to REI, a good source for tall sizes in outerwear and general purpose clothing. Like REI, they sell cycles and cycling gear, but nothing particularly geared to the tall cyclist. Again, search for "tall" on their site. Lifetime moneyback guarantee.
Aerotech Designs: Aerotech is a good source for tall jerseys and cycling tights. Reasonably priced. Solid colors only, as far as I can tell.
Peter White Cycles: PWC is a vendor of specialized cycling equipment, particularly French cranksets by TA (which are still available in 185mm crankarm lengths), lighting systems, and custom-built wheels. Peter will build you a bulletproof set of wheels for your bike, and guarantees them against spoke breakage. These are really a good value if you know what you are looking for.
Brands Cycles: Brands is another online cycle vendor. They seem to have a good selection of large-size shoes.