Lots of great designs out there. I have two different sized Paris sleds with homemade PVC pulls, plus an old Mountainsmith Pulk (same design now sold by Kifaru).

Here's one that rolls up and is lighter than the kit at Sportsmansguide:

http://www.northernsledworks.com/Pulkwebpg.html

(I'm the winter gear editor for Backpackinglight.com and also run a small pulk makers forum in Yahoo groups; currently inactive, but has some good links and posts in it if you want to seek it out.)