You are probably best off at the clubs and possibly the casas if you find some good ones. (I only know of Casa Marujas, although Club El Oasis appears to more of a casa, than a club, I did not enter)

Unfortunately, most of the clubs are closed until the evening and Samba is the only one I am aware of that is open on Sunday.

For those times when the clubs are closed, or if you simply want to try some independent alternatives, you should probably pick up a copy of Prensa Libre, a local newspaper for Guatemala City. Escorts are listed as "Maseje" in the classified section under "Varios".

Prensa Libre also has a website at www.prensalibre.com. You can access the "Varios" section directly at http://www.prensalibre.com/clasi/list.jsp?sub=14&anuncio=24.

I did not call any of these numbers, so I cannot comment on these types of services.

Here are a few escort sites I found while perusing through the Prensa Libre classifieds. I couldn't find any good sites with a Google Search.

http://www.grandesofertas.ya.st/
http://www.enlasex.net/
http://www.geocities.com/cindyguate
http://www.icebodys.com/