I can use Bayphoto for a 30x10 and cut but it would be simpler if this size were available somewhere.
Paper is sold in stock sheet sizes or rolls directly from the paper mills. Print shops can print most any size you require but they must buy paper of adequate size and then trim away the excess. Most print shops charge a modest extra fee for trimming.
Does that answer your question?
Thanks. I will likely call them to get a price.