I started a small business with a retail location and would like to accept Bitcoin for purchases (via customer credit card).
That question doesn't make sense. Bitcoin and credit cards are entirely separate things. It's like asking how to accept cash or gold for purchases (via customer credit card). Do you mean you wish customers to continue paying by credit card, but have the funds converted to Bitcoin instead of deposited into your bank account? No such service currently exists (and probably won't ever due to chargeback fraud), though if one did accepting credit card payments though it would be no different from any other payment processor. Banks would necessarily still be involved, since you can't have credit card transactions without them.