Some information here about Mini DisplayPort (and Thunderbolt), and display support:
http://support.apple.com/kb/HT3382
You have two Thunderbolt ports.
So, it follows that you can connect two Thunderbolt (TB) displays.
Amazingly enough - you can connect displays with Mini DisplayPort connectors, as TB uses DisplayPort for video connections. The TB and Mini DisplayPort connectors are physically interchangeable, at least when connected to TB ports.
If you are using chained devices on TB, non-TB displays MUST be the last device on the chain (or the only device)
You have two TB ports, so you should be able to connect two non-TB displays, one on each port.
Additional free advice - ask Wacom tech support about this.
And/or ask the free tech support folks at OWC (macsales.com), who should also be able to supply you with an answer.
My best advice - find a way to try before you buy, particularly with the Cintiq.
Finally, looking forward, multiple display support in the upcoming 10.9 (Mavericks) purports to add much more support for use of external displays -
http://www.apple.com/osx/preview/#multiple-displays