Canyon Explorations/Expeditions may have some kayak spots. Arizona Raft Adventures may as well, but the AzRA trip I saw on the water was a charter. It may not be a regular thing. Can-X requires a minimum of four kayakers for any to go on a trip . The NPS also requires a kayak guide for any paddlers. Colorado River and Trails Expeditions runs one kayak trip a year. Do some research and I'm sure you'll find something. Check out www.gcroa.org
, find the outfitters tab, and click your way through there.