Fixed wheels are as easy as fronts to build as you dont have to dish. Just lace and tension.
Do the initial tighten from inside the rim with an electric drill/driver. My first one took maybe three hours, and I was going slow, drinkin beer and being methodical. The lacing part is easy--but I still had to use a guide to remember the order.Getting them up to tension while keeping the thing round just takes patience. True it in the upside down frame of a bike with pencils rubber banded to the stays to keep the rim centered.
Its something to do instead of going out on a Friday.Three hours and dont forget the beer to keep you loose.
I think any capable person should be building them in under an hour with a little practice.
http://www.sheldonbrown.com/wheelbuild.htmlDo a standard 3X. Its strong and very simple to lace if youre systematic about it.
Dont forget to stress relieve the spokes to seat them in the hub flange. My new fave way of doing this is to put the hub axle on a block of wood and firmly press down on the rim, working all the way around and both sides. This will also relieve any wound up spokes.
I cant wait to build my next set, makes you feel like a real grown up wrench. Im still grinning from the first three I built--that are all still true as the day I built them.