Bicycle Tutor

I visited 3-4 LBS and none of them stock rims or straight-pull spokes. I am ready to try my hand at wheel building and have my 20h front hub in hand. Where do I get a rim? How do I choose a rim? I am currently running a Shimano wh-550 wheelset and would be only too happy to build a set of wheels with nipples at the rim instead of at the hub (especially at the rear)!
...j

20 hole rims will have to be something special. Probably deep section for strength.
You maybe have to order over the Internet from a specialist shop.
Check that your hub is suitable to match the rim and spokes?

Well, the first online shop I checked has them: http://cnc-bike.de/product_info.php?cPath=39_187_886&products_id=6239&osCsid=3ed78aa68985776f10152dcabeefbbad
Not much help to you, though, since this is probably on the wrong continent...