Banh Mi in the Inland Empire?
Is there any? Where? Is it any good? What do you recommend?
Unless there's an area with a significant Vietnamese population you aren't going to find any Bahn Mi.
There's a Vietnamese-run Market in Pomona. I wish I remembered the cross streets for you. If you drive down Indian Hill from Claremont, you make a right at Pomona (memory very fuzzy here). There's a pho restaurant in that plaza and they have sandwiches. Of course, this was at least 4 years ago.
There are a couple of places that I know of in Riverside. The best is Pho Saigon on University Ave.