Looks like the Western Massachusetts Regional Library System has something similar to what Susan Babb posted: http://www.wmrls.org/services/youth/cbr.html
Here's another one: http://www.tristatereviews.org/ (PA, DE, NJ)
Southwestern Ohio Young Adult Materials Review Group: http://soyamrg.weebly.com/
Three more:
South Jersey Regional Library Cooperative Book Evaluation Program:
http://www.sjrlc.org/bookeval/
Alabama Library Media Online (reviews are online, not sure if they have in-person mtgs):
http://alex.state.al.us/librarymedia/BookAwards.html
Southern Maine Library District:
http://www.maine.gov/msl/smld/services/children.htm#review
Just got a response on YALSA-BK:
I am a member of THE YOUNG ADULT REVIEWERS OF SOUTHERN CALIFORNIA who review materials for teens grades 6-12, ages 12-18...
we meet monthly and would love more publicity and more items to review, as it's up to us to pound the pavement at the exhibits at midwinter and annual, getting publishers interested in sending us materials...
website info is sketchy as we have been changing our affiliations- presently it's the following, with our reviews to be posted soon...
http://www.socallibraries.org/reference, go to age specific, and then YAR should be under that ...but it's not there right now! dont know why...
address is Young adult reviewers of so cal
% inglewood public library
101 w. manchester blvd
inglewood, ca. 90301
i am the contact for publishers...
drue wagner-mees
lapl
brentwood branch
wagndragn@aol.com