On scams like this, I have seen people bid $5,000,000 and then someone else (planned) bid "a few million more" so it "shows up" as a high bid. This certainly gets ebays attention. Since we all KNOW this piece does not exsist, I don't think ebay will hold you to anything and they may just charge the seller the huge fee (percentage) for the sale!
Interesting saga. I hope Scotland yard finds this person and shackles them up for a few years of stale chips.
PS, I don't know the legal ramifications of bidding millions of dollars on something. Certainly, ebay can't hold you to an item that does not exsist. The fake serial number is the key.