So I've ordered a few pieces of gear from small shops over the past year. Not custom, designed to make specifications gear, but off-the-shelf designs that these companies are actively promoting at the time. They make them - sew, mold, whatever - by hand, one at time, so predictably there is a wait time involved.
The problem comes when you state a wait time...and then blow past it without update. So 3 weeks turns to 6 week without notice, 2 weeks turns to 5 weeks.
All right, so it's taking longer than expected. I understand. Shoot me a note.
Even if you don't shoot me a note to say "hey, looks like we're going to take a bit longer than we thought", you can at least respond to my e-mail kindly looking for a status update.
If you've got so many e-mails coming in asking "Hey, you said to expect a 6 week wait time, it's been 12 - any update?" that you can't keep up with them, you need to hire some help, jack up your prices or do something else differently.
Blowing past the time frame you've established, no proactive notice and no response to your customer's inquiries is just not an acceptable way to treat customers who have already paid you.
If someone did that at an office job - blew deadlines, didn't communicate - how long do you think they'd be employed for? In the private sector, not the government.
Raven Concealment - though they are probably 'big time' in terms of custom gear - has developed the communication model to imitate. They set expectations for wait time at the outset and then send out an e-mail update every step of the way. Really, you get 4 or 5 e-mails from them. If anything, they really probably over communicate your order status - removing the lingering question of "Did they forget about my order? and "Did this dude just run off with my money?"
Of course, a one or two man shop is not likely to have the bandwidth to send every customer 5 e-mails communicating their order status. But come on guys, no matter how awesome your gear is, if the customer experience is sucky and generally unprofessional, how successful do you think you'll be?
Edited to Add: ANY communication with your customer is an opportunity to wow them and continue to build loyalty and enthusiasm for your work and brand. How companies deal with slipped deadlines, mistakes and whatever can be defining positive moments for customers...or they can burn bridges.