I believe that
A&I in L.A. can take 4X5 via mail. call them...
323.856.5280
also, Carl's Darkroom is VERY FAST! i shipped the film (4x5 and 120) e6 via USPS Priority, and I had it back in my hands within 4 days or so. Very accomodating, and very friendly people. Pretty reasonable pricing as well.
here's their number (they're in Colorado)
Carl's Darkroom/ Digigraphics
970.482.8595
link to their e6 order form
http://www.digi-graphics.com/forms/e6_mail_order/e6_mailform_page.html
I use A&I when I'm in a rush (i try to process ALL my own film), but A&I does a terrific job, and Carl's Darkroom/ Digigraphics did an excellent job and the quick turnaround was a welcome surprise
best of luck