Darrin, head honcho at Extreme Gear Labs, started a thread recently where he dispenses some wisdom about getting into the gear making business. The short version is that, much like pimpin’, gear making aint easy. It takes certain specific skills to do it well and the margins are probably not as padded as you might think. Check out the thread at M4C before you buy a sewing machine!
Darrin, AKA Egg Roll, also shows a very, very slick lumbar pack that he has been working on for some time at the link.