I'm looking to buy a new ADF scanner, the one I have is built into a printer and is getting past it. I'm looking for something that can cope well with till receipts too, which mine doesn't.
We use Fujitsu fi-6130 scanners, absolutly brilliant.
You can imagine the amount we scan at the ICB and they handle it fine, any shape or size (letterheads, business cards, leaflets) and the accounts department use it to scan receipts.
There are smaller versions which might better suit you, as far as I can tell it is only a reduction in speed and size of the ADF (think the 6130 is about 80 sheets).