The Thule 421 Xsporter truck rack is an excellent solution for transporting a kayak in your 2000 Chevy Silverado truckbed. You can then connect something like the Thule 883 Glide-and-Set kayak rack directly to the Thule 421 Xsporter front and rear load bars for transporting your kayak. FYI the 421 Xsporter also does come with Xstops which are a nice carrier for items such as a canoe, lumber, ladder etc. You might also want to checkout this
page of chevy truck rack pictures or this
list of chevy racks photos for an example of this system installed on a Chevy Silverado pickup truck.