Your best bet is to contact each website that you think is trustworthy, tell them that you are a premium user (your money proves that) and ask them to offer you special limits. In exchange, you might be requested to provide many proofs, i.e. how you got money, what is your source of income, they might check how clean your coins are, they'll ask for residential and other proofs. You probably should have thought about that a little earlier but anyway, I think that this is your best possibility. No website accepts up to 1 million usd bet for a regular customer.