Flup,
Heather and I were asking the same questions a few months ago, since we're leaving for Mexico (with Megs in tow) this week!
ProTech came very highly recommended, and several of the staff are here with us on RBW. They've got bottles (Rebreather and bailout) as well as sorb available for you. Drop MattMexico or MikeDive a line and they'll get you all taken care of.
Brian