Blinkbox Books ?
Glad to see you have included Sainsbury's eBooks. Perhaps you will consider Blinkbox Books (Tesco) when they are up and running ?
They don’t have an affiliate system, so I can’t make any money when you buy a book from them. I’m thinking about bundling support for such stores into a subscription service; would you be willing to pay a small monthly fee to get access to the prices from more stores like this?
helen white commented
Great idea, they have a good selection and prices seem reasonable