The major bitcoin exchanges could easily handle that kind of volume. The payment processors should be able to handle it - they might have to use an exchange themselves if they don't have it on hand, but if they're competent that shouldn't be a problem.
The casinos would receive this money from the provider since it's a progressive, so if they can't pay it out entirely in a week or two with a bitcoin transaction, it's because they just don't want you and would rather have that money sitting on their site for months for you to play it back. (The actual bitcoin transaction itself takes minutes and costs like $2 for any amount sent, but it may take time to move money from RTG to casino bank to payment processor or btc exchange). Dealing with actual U.S. banks might be a more difficult issue in terms of paying out that kind of win, but casinos also use that as a convenient excuse to pay slowly.
If given the choice between being paid over 6 months to a year or being exposed to a few hours of bitcoin volatility, personality I'd much rather take the risk - but like I said, many casinos will still probably drip pay you even with bitcoin since they see a gambler forced to sit with money in their account for months as easy money for the taking.
I'd be curious if any of the accredited casinos here would pledge to pay out progressives in a lump sum, at least for bitcoin withdrawals. It's harder to guarantee you can send $200k through the U.S. banking system as an unregulated casino without raising flags.
