Boomer,
The casino aboard MV Grand Princess had both $5 and $25 blackjack tables as of last October, which surprised me because it was the first time I had seen a blackjack table aboard ship with a minimum over $5. The last time I visited a casino aboard a sister to MV Dawn Princess, the minimum was $5 at all of the blackjack tables but it's possible that they have changed the policy so that some of the tables have higher limits. Still, I suspect that you will find what you are after.
Norm.