Hi cassieheart,
Did a simple design for you. It is memorable and unique.
User should catch the nature of your business easily even without the site name "bit" and "bay".
(replaced by "B" from bitcoin logo and another "b" from the trolley)
I didn't want to show the hyphen, but couldn't have "bitbay" as a single word.
So I put "bit" and "bay" on either side of the trolley, just to remind users is "bit-bay".
Hope you like it. Comments are welcomed.
http://i43.tinypic.com/29qnupt.png