There are available prelim peds years. Here is a list of the programs from last year, per the NRMP and how many spots filled. This does not include special arranged prelim years by talking with program directors.
UCSF - 1
U of Louisville - 3 (none filled in 2008)
Johns Hopkins - 2 (1 filled)
Mass General - 2 (1 filled)
Children's Mercy in KC - 2 (1 filled)
NYU - 1 (unfilled)
SUNY Brooklyn - 3
U of Rochester -1 (unfilled)
UNC - 1
Cincinnati Children's - 1
Oklahoma at OK City - 1
Oklahoma at Tulsa - 1
Geisinger PA - 2 (unfilled)
St Christopher's in PA - 2 (unfilled)
UT San Antonio - 1 (unfilled)
U of Washington - 1
Med College of Wisconsin - 2 (1 filled)
These do NOT include peds prelim programs specifically designated for child neuro (i.e. 2 prelim years). The only one in cali through the match is UCSF
Part of this depends on why you are doing a peds prelim year. If you are prelim-ing for anesthesia or radiology, i have heard from many people that doing only peds prelim puts you at a disadvantage because of your lack of adult medicine knowledge. Just an FYI 🙂