Forum Moderators: buckworks
When it comes to hosting an ecommerce site with shopping cart I find it best to find a host who can handle (or will agree to work with) the shopping cart software you want to use. Some will not be able to do this as shopping carts can put a strain on servers.
IOW, first pick the shopping cart software you want to use then find a host that can deal with it (while not necessarily providing support for the shopping cart per se).
If you want to farm the job out I think it is critical to have a detailed definition up front. If you go through e-lance, you'll probably get bids from lots of people who have done carts before, that they can just modify for your needs. Make sure you define the functionality you want in detail.