I ended up buying two maps from a vendor I saw there (I actually didn't buy at the fair but contacted him months later to see if he still had them) who I don't think specialized in maps at all, but had a real range of materials for sale, the maps I chose being the apparent exception to the rule.
Here's the map, and what I've learned about it follows:
This is a projection of north east Africa, primarily Egypt, printed in 1561 by Girolamo Ruscelli.
Ruscelli himself was an interesting guy. He was into a bit of everything, including cartography, and apparently published a 'book of secrets' which aimed to answer some basic scientific questions, provide advice on matters related to science and perhaps dabbled in some alchemy as well.
This map is one of a number he published in his revision of Ptolemy's Geography. There's a link to it, with a high quality image here, where you can see it's on sale for USD$125 (I paid much less for it, which is very satisfying).
There is much that I don't know about this region, and it's difficult for me to comment too heavily on the map, but when I saw it, having been to Egypt, I knew I wanted it.
The map has some interesting elements, for example, showing off the cities of Cairo and Alexandria. Having a strangely representative delta of the Nile, and showing what appears to be some sizable islands in the Nile
The map also seems to show the Nile having three southern branches, different than the two (Blue and While Niles). The rivers on the map are not particularly well labeled, however, so it's hard to be sure what they refer to.
This is one of two maps by the same cartographer I bought from the same vendor and it's interesting for its age, the history behind it and it's producer and of course the subject matter. Egypt was and is a source of fascination to many for many reasons. I'm lucky to have such an early representation of it.