Here is the link for the universal fit window channel from J.C. Whitney.

http://www.jcwhitney.com/autoparts/Search?catalogId=10101&storeId=10101&sku=ZX193464U&searchbtn.x=13&searchbtn.y=15

These are flexible and can be installed with a little persuasion from a rubber mallet.  Also,  just cut the corner at the upper rear of the channel at a 45 degree angle to get it to fit properly with the one running up the back of the door.  It fits really snug.

"when installing use a little wd40 or silicon to lubricate the window channel (inside) and also make sure you have a good rubber hammer.  start at one end and tap into the channel as you go make sure to tap in real good at the corners..cut with a drimiel tool and your done..."

All of this info is from whizzo1998 from the Yahoo! group: FORDPINTOSTREE TMACHINES.  I have yet to purchase a set for myself, but I know he knows what he is talking about.
--Doug