Consider 9 speeds and XTR rear derailleur. Gives us great results with our normal 11-28 cassette, and we can throw on 11-32 or 11-34 for mountain rides without changing anything else.
Other: Ultegra front derailleur. Ultegra shifters. Ultegra octalink crankset. Get great shifting, including triple front. Re-tuning after assembling our S&S coupled bike at the destination is not a problem, despite what mtnbke says. Dura Ace caliper brakes work great. Sometime we add a disk on the rear, controlled by stoker, if anticipating major descents. Have had variety of wheels over the years, liking the current Phil Wood hubset built with Velocity Deep V's and 36 spokes. Our frame only handles up to about a 28c width tire, else I'd probably consider the Mavic A719s. Also have an older set of WI hubs with daVinci V-22 rims, and these were OK, but broke too many spokes at inopportune times (but maybe a build issue, not equipment). 320 lb team. Let us know what you decide.