Well, sort of a roadtip quest I guess...
This is a fairly funky question for this forum... you might be better advised to try the specific question on a photo forum.
For some different ways to check on it..
- Check also some of the larger office supplies/ stationary companies. They carry digital cameras (the G7 is at least on the web sites), and I've bought a recent digital camera at a similar store (an amazing sale, since the line was being discontinued). These could be companies like Staples, Office Depot, or Office Max. I know they're within 30 miles of Dulles.
- Check the general electronic retailers. Circuit City, CompUSA, Fry's Electronics (but I don't think they have stores east of the Mississippi), BestBuy, Radioshack, etc. Also check Target and Walmart. I know there are Circuit City's, CompUSAs and Targets in the area as I've shopped in all of them within 30 miles of Dulles. Believe it or not, Gateway Computers lists carrying the G7, and they at least used to have storefronts around the country. And Radioshack does carry the Canon line of digital cameras, but I don't see a reference to the G7. (Radioshack has regional "superstores" which are usually pretty well stocked, I've found.)
- Places like Ritz Camera does have storefront locations. I bet one of the local malls has a Ritz Camera (or their competitor) storefront.
Lastly -- a couple of wild options. Email or call the local store, and ask them to order one for you and hold it for you to pick up at the store. Can't hurt to ask, if they don't have one in stock. I've done the "pick up at the store" option through Circuit City for computer hardware, but that was for something in stock -- but you can ask if they can get it from their warehouse and hold it for you.
And if you're going to be in town for a couple of days, you might consider buying it from someone like Amazon and having it overnighted to your hotel or office.
You know you will have to declare this on customs on the way back, right? It might be under the personal exclusion limit (no idea what that is...) but keep the receipt. The Tax folks always want their share, no matter what..
From a general roadtrip standpoint, I've had packages overnighted to hotels I was going to be staying at, had packages picked up as "general delivery" at local post offices in places I was going to be passing through, and similar things when I've needed stuff on the road. Not for a while though... but there are options for this.