Hey. I know that https://cryptonex.org allows buying btc with a cc online. I bought some and it was very fast and safe.
As for the limits, their site says: daily limit up to $20000. Monthly limit up to $50000. Still, you can write them and tell your intentions. They are sure to offer you some perks;
Contact us for the deposits higher than $ 50 000 for mining – we will provide you with bonuses, preferential prices, etc.