18TEN Designs is a fairly new company that does railroad art - logos and such - for decorating the train room. They were a vendor at last summer's NMRA National in Michigan, and I won a gift certificate in a raffle drawing. 18TEN worked with me to custom-design a plaque for the Bath & Hammondsport RR, which occupies the lower deck of my layout. Although a bit pricey IMHO, they did a wonderful job and I'm very happy with it.
www.18tendesigns.comThis is an 18" diameter logo:

Sadly, I took this with my cell phone and can't seem to orient the photo as a portrait here, even though that is how I took it. Hard to get good help these days.
Ron