Well, since time is running out I think we'll switch to the Galaxy Tab. And yeah, I'm running a Vibrant Galaxy S, and my partner has an Epic - but it's just more convenient to have our customers signing on something bigger than our phones
Yeah, if you have any need for it, Square is great. The card reader just uses audio, so it can (technically) work on anything with a 3.5mm jack, it doesn't even give me access to the credit card information after I've swiped the card (protecting the purchaser). It emails you a receipt if you'd like, which contains a google map of where you made the purchase at.
I hope to be back with another Viewsonic G Tablet at some time though, great piece of hardware, and hands down the best early android tab out there, and viewsonic seems really dedicated to it as well. Despite me having Samsung, they're not the best in keeping up with Android OS updates.