Don,
No info on film supplies, but I wanted to say that Merida is a great city. We loved the local mayan cuisine in the region, and Merida is nice and modern (they even had a Costco if I remember correctly.)
We spent 2 weeks in the Yucatan, starting in on the east coast and ending in Merida. The local people were very friendly, and the ruin sites were amazing to photograph.
Good luck with the move!
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