Just helping with the verbiage:
Those faces are off "front-lit" or "internally illuminated" channel letters.
"Back-lit" channel letters have acrylic/polycarbonate backs and are typically referred to as "halo-lit", "reverse-lit" or "back-lit".
If the faces and backs are acrylic/polycarbonate, they're typically referred to as "dual-lit" channel letters.
If you get rubbings of the letters, any electrical (and some non-electrical) sign shop can make those.
its just acrylic with trimcap material. easy to make your self. 'pop' the old trimcap off, use the existing letter as a template, cut new acrylic, decorate, then put new trimcap on (using weldon thin first, and then a bead of thick)
the trim cap is what is throwing us, letters and vinyl are easy to produce
why did you change the title to halo-lit? what you show is a regular channel letter face
to the OP (and txfb....): this is what halo lit letters look like
edit: @kgirl you may be saving a bit of money with 3/4" trimcap, but you are lowering the lifespan of your letters - way more susceptible to breakage during service.
I'm sorry you get breakage and lower life span using Plasco trim why?