I have a Ritchey Breakaway Cross bike that I plan on touring with. I equiped the bike with Campy 10spd Centaur triple group. The crankset was a 30-40-50 and I replaced the small chainring with a T/A Specialities 74 BCD 26t ring. The Cassette is a 13-29. The gearing is very low with that combination. The wheelsets I have are 32H laced to OP rims. I am getting a set built of Centaur hubs 36H laced to the DT Swiss TK 7.1 rims I will use a 700cx28 or 32 tire (conti top Contact) for my actual touring. Meanwhile I use the bike with Conti GP4000 for the road and Conti Twister 32s for off road riding. I like the shorter wheel base of the cross bike for the versatility of being an all around bike. The Centaur Ergos work very well with the Cantis when adjusted properly.
I will be modifying a rear rack for improved kick room and plan to use low riding front paniers to distribute the load. For a fork I will be replacing the carbon front fork with a Surly steel cross check fork with the brazons to mount the front rack.
I have talked to several people who have used the BOB for loaded touring had had no problems pulling the trailer (comment was have a low enough gear ratio for hills).
I helped a friend obtain low gearing for their Shimano triples by replacing the RD with an XT and installing an 11-32 cassette. There are always options.
Any comments on using the low front rack on a cross fork?