We were thinking of picking up a second set of wheels for our semi-slick tires. The intended purpose is for riding paved trails, rails to trails, or street cruising. I've seen some great deals on wheel sets spec'd with Rhynolite rims, 14g spokes, and xt hubs. Would this combo be reliable with our total loaded team weight (including bike) of nearly 400lbs? Any suggestions as to alternatives?

You'd be hard pressed to find a more economical combination for a tandem. Shimano's XT hubs use the same "guts" as the Tandem Specific HF08 hubs mentioned in a recent thread on the subject of hubs... so no worries there. Rhynolite's are also a tried-and-true tandem rim. I tend to build tandem wheels using double-butted spokes, but for a 26" fat tire bike the straight gauge spokes wouldn't bother me.

Of course, a wheelset is only as good / reliable as the quality of the build so the real question becomes, who's offering them and how's their reputation relative to the reliability, strength, and trueness of their wheels? If the firm offering the wheels does a good job of tensioning, distressing, and trueing the wheels s
they should be more than adequate... 36h F&R OK, 40h rear even better.

Unfortunately our local bike shops rarely build cheaper wheelsets anymore. I suspect they purchase their in-house stock from a wholesaler. I was perusing the major catalog companies which mostly offer 32 3 cross versions.