The systems are very adaptable in my opinion.
First of all, I think that Chaos in Cairo can be used to represent almost any early 20th century genre. The warbands (excluding the mummies) contain the followinh character archtypes:
ARCHAEOLOGISTS:
expedition leader
expedition sponsor
professor
guards (i.e. generic bodyguards, thugs, police detective, etc...)
foreman
diggers (unit of henchmen)
CULT OF SET:
cult leader
dark priest
acolytes
bodyguards
sons of set (unit of henchmen)
SWORDS OF RA:
(great for any less advanced or tribal group)
cheiftan
warriors
mystic
dervish
tribesmen (unit of henchmen)
AND THEN MERCENARY CHARACTERS
bedouin guide
big game hunter
doctor
holy man or woman
reporter
street urchin
two-fisted archaeologist
As for periods other than the 20th century, Scott Pyle also wrote
Goalsystem Fantasy (available as a PDF for a few bucks) which has the added advantage of containing the points system. In other words, you build each character from the ground up by buying its attributes, skills, and equipment.
Finally, we recently used Chaos in Cairo to play a Weird Wild West game.
Here's the explanation:
http://geektactica.blogspot.com/2010/06/playing-weird-wild-west-with-modified.htmlHere's a game report:
http://geektactica.blogspot.com/2010/06/when-dead-comea-knockin.htmlGood luck with it,
J