Update: I purchased and attached a powered USB hub last night, a Belkin 7-Port model. The adapter is 5V-4A (!), and seems to completely meet the needs of the Interface Kit. So far so good.
Hardware summary for others who may have the same need:
--1 USB Extension Over CAT5e (#USB-1370, Cables Unlimited)
--1 Hi-Speed USB 2.0 7-Port Lighted Hub (#F5U700, Belkin)
--50" of Cat 6 patch cable
Thank you again,