GameStop bids $55.5B for eBay — and a 135M-buyer Bitcoin payments test could come with it.

GameStop made an unsolicited $55.5 billion offer for eBay on May 4, proposing $125 a share in a 50/50 cash-and-stock structure that carries a 27% premium to eBay's 30-day volume-weighted average price. The cash portion would draw on GameStop's $9.4 billion balance sheet plus up to $20 billion in…