I just hope they will be an Urban Explorer class, if not in the base book then in one of the supplements.
A regular old Explorer does pretty well as Urban Explorer, especially if you take feats that help more in an urban environment. Pathfinder Basics: Urban and Night Training probably help the most, and then chuck in some chance feats and he's ready to rock. My FC explorer was purely geared towards urban environments and did fine without modification. Quick research checks can be casing places, gaining clues about them and reliable Athletics also makes you pretty good in a foot chase / as a free runner, not to mention being hard to grapple.
I wouldn't worry about a specialised class for this sort of role, so much as a few more "urbanised" terrain feats, because I don't expect 10kb to take place in jungles, or on open plains.
EDIT: I would also like to second Nepenthe's sentiment, just for the record.