How big is this market? Do you have a clear value proposition which will show bands (who are probably strapped for cash) how spending money on the jackets (which look like an interesting concept), is going to translate to more sales?

What are the margins like on this kind of business? How much will it cost to acquire a customer? Who are your competitors?

I would say in terms of direct response the biggest thing missing is you don't have a pic of a sample jacket.

Also something 90% of people forget. Give a stronger reason why someone should opt in to your beta?

Maybe put a quote (social proof) under the sign up form?

I'd also think about split testing the color and wording of that beta sign up button. It subconsciously remind me of the FB open graph login and some people don't like signing up that way (some do - so ABT...Always Be Testing)

good luck