The only thing I found (that I use) is the payware Fly To Cancun scenery found on Simmarket (outside of the scenery this package is pretty crappy; It's only installed on my machine for the sole purpose of the scenery). With this scenery you get many of the major airports in Mexico including MMMX and the surrounding city. I never could understand why some great renditions of Cancun airport are released without any thought of how void the area is in default FS9. The area is nothing without the hotels visible on approach with accurate landclass/coastlines... Fly to Cancun gives you a somewhat o.k. rendition of the hotels, landclass, coastline, and peninsula that's actually a huge improvement over default... You can disable the airport supplied with Fly to Cancun and insert the better options that's out there. I hear FlyMex offers a nice rendition of Cancun but I've never seen it. I've included the links to both options. If I were you I'd go for Fly Mexico and post some screenshots of the hotel peninsula area. I'd love to see how this package beefs up the area although I'm curious there's no Cancun 'area' shots are on FlyMex's website (just one of the airport). Fly to Cancun may or may not be the best option for the hotels area but it was when I was looking a few years ago (pre FlyMex). Since I don't fly to this area allot I opted not to bother with Fly Mexico which looks like the better option if they did anything meaningful to the Cancun area outside of the airport.
http://www.flymex.com.mx/MEX2004V1/MEX2004eng.htmhttp://secure.simmarket.com/flightsoft-fly-to-cancun.phtml