Colorado Joe:
The Thule Track Rack Pro is an excellent choice; And, it is available in a black-powder coat. Actually, I purchased my rack (from RealTruck.com) for virtually the identical reasons you wish for; surfboards/SUP, kayaks, bikes and winter sport gear. And, the racks are well-constructed and strong enough for transporting reasonably weighted construction materials. Two kayaks and/or multiple surfboards fit securely and load with ease. About the only caveats are it takes patience, tolerable effort and time to both mount and remove the racks. Furthermore, I've not discovered a truck bed-cover that will integrate with them. Until such a time of hopeful availability and compatibility, I'll continue simply using a tarp and readily available stretchable bed-webbing to cover and secure bed contents. As to fully-loaded bed/rack effects upon my trucks mileage numbers; 10% or so decline, depending on driving habits and conditions. Seemingly rugged enough for mild off-road adventure, I've found this Thule Rack system to be an excellent, flexible, rugged and reliable choice for the Colorado.
