Treasure Island in Welch, MN has more levels in the latest 14th issue Island Passport cards where the phone number and web address are now on the bottom line of the reverse. Previously only the base Ruby level was known but Sapphire, Emerald and Pearl levels have now been reported. And there are two variations of the Pearl level, the second having an "01" in the top right corner on the reverse above the mag stripe. If anyone finds additional levels or cards with different numbers on the back please let me know and/or send scans so we can get them documented.

And here's the back of the Pearl with the "01"...