Update 14/12/05:
We are sold out, but GameStop just listed two new Xbox 360 Bundles that are in stock now.

I could not believe it at first, but our supply manager for our I4U Shop was able to secure a limited number of Microsoft Xbox 360 bundles.

Those Xbox 360 bundles are not a bargain, but they are in stock. I asked twice, if those Xbox consoles are really ready to ship, and they are.
I know those prices are very high, but we cannot get them cheaper on the market right now. The shortage on the US market enables suppliers who saved their stock to cash in on it.

There is for instance the Xbox 360 Premium Gold Pack Mega Sports Bundles, which is selling for $1,196.80 .

This bundle includes a Xbox 360 Premium, Xbox Live Silver membership, Xbox Live Gold 30-day trial, Bonus Media Remote, Madden 2006, Tiger Woods Golf and NBA Live 2006.
There are four Xbox 360 systems and bundles available in our I4U Shop starting at $854.85 (Xbox 360 Core system).

Only other source for Xbox 360, we know of is eBay. Check also Shopping.com for daily changing listings of Xbox 360 offers.