Mural/Composite Source

I have a question which I didnt think was that strange, but apparently, it is. I am trying to come up with the best source for a big mural/composite picture. I have a client that has one long blank wall in their office and they want three big pictures that make one wide picture. After much time with a tape measure and the client, we have decided that we basically want three large canvas panels with the pic to stretch across all. There would be a little space in between for effect. But basically each panel would be 48" by 48", but the biggest that I have been able to find is 40" x 40". I shot the pic on the D800, so it is plenty big. Luckily, cost is not really an issue for these folks, but I don't have a good source. Any suggestions???

I would try Bay Photo.

They have 40x40 and 40x60 listed in their standard sizes, but I know they do custom sizes as well.

I know of roll printers that go as wide as 64" so your size is well within range of what print shops can do (8" on each edge should be more than enough extra space to do the wraps). Don't have a source, but I've seen Bay mentioned before for work like this, though it seems from their custom sizing that 40" may be a limitation on one edge. Given 'em a call.