You know how there are rollercoasters/rides that take your picture
during a particular drop or loop and then as you exit, you can see the
picture and for a fee, get an instant digital print of the picture
placed in a simple frame?

Or during a theater or dinner show, your picture is taken and right at
the end, you are offered the picture to purchase as a souvenir?

Well, I am looking to find vendors that offer this service on a
smaller scale in Southern California for events on a hired basis.  How
it would work is:

-A photographer would take a staged digital shot of each group for this purpose
-On-site using a portable color printer, the pictures would be printed
and placed into simple frames.  No actual "1 hour print" would be
needed in this case to save some cost.
-Provided to the groups at the end of the event
-A cd of all the digital pictures probably would be needed too
The time elapsed from the time the digital picture is taken to the
print delivered could be 3-4 hours (the time to take all of the
pictures and print them all out from the on-site color printer brought
for this purpose).

I don't know what type of keywords would work specifically for this
type of service.  I am looking for vendors who do work primarily in
Southern California (Inland Empire/Los Angeles/Orange County), and if
a few vendors of choice (to find lower cost option for example), that
is my need.