Peanut Butter and Jelly is such a comfort food for me - I grew up on these things. Though I gotta say P.B. Loco's are likely a little better than what Jif and white bread used to make.
I found this place by accident just wandering around Fashion Square mall, and what a find! They have several breads, peanut butters, and jellys to choose from, and a dozen wacky creations of their own. For example a BLT-PB - Wow! However they should add mac-n-cheese to the menu.
http://www.pbloco.com