You can go to
www.napaonline.com and do a vehicle based search. They've greatly revised their website and it's very easy to do a parts search now. Also allows you to "reserve" a part, so that the store you select will get it shipped in from the warehouse and they'll give you a call when it arrives, and you pay for it when you pick it up.
Matter of fact, I was doing some research on their website the other day, looking to see if they had a master rebuild kit for the rear diff, and came across greaseable u-joints for the rear driveshaft.
Another place you can check for greaseable u-joints is Tom Woods Custom Driveshafts,
www.4xshaft.com . I've got a set of his Gold Seal greaseable u-joints on my CRD.
As far as the clamp on the rubber boot, you can pick up metal tystraps at Home Depot in the Electrical department.