I can take care of user interface side of it applying beautiful expressive interface, when it comes to shopping carts i wont be designing from scratch so we will deal with third party trusted entities to get ssl certificates etc.
for pcb spec + gerber files I need more details on why exactly you need them done.
there are few out there they come at various costs, lets worry about project before any financials.
let's talk it more in details.
Cheers.