<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Shareholder:
Most likely all the STAR-affiliated ones will be closed, since they only open within hours of the departure of TG and SQ flights. MX does not operate its own lounge, and the official STARGold lounge here is the RG one, which is open limited hours.</font>
Actually, there is an MX Frecuenta lounge in the TB Int'l Terminal. It's located next door to all of the other *A lounges (ANA, LH and RG if I remember correctly) on the 4th floor... Shareholder is right about access though - they only seem to be open around respective departure times.
You could also try the AC or the NZ lounges over in T2, but it's a looong hike to T7 (UA) and they may not let you in.
Check out the
Global Lounge Project - it's a nice little tool to survey lounges around the world.