Just one question, have you priced the mounting and acrylic cost? On a print that large, unless the location is really clean, you will get something under the acrylic and it's a one trick pony. Also, that is a lot of Acrylic to scratch, and it will somehow get scratched. I know it looks great but when it all comes down to it, most designers, won't pay the price unless the location is aware of it, costs involved etc.
Your idea of canvas is a good one, easy to work with, and you might try the Breathing Color or Moab Metallic canvas. I believe Moab has one now, I know BC does.
Most places I have worked with, with an image that large, are using a firm that can print onto a panel, then the panel is just placed on the wall. Not sure of the process as the work I have done was all printed and then placed in the location.
One other note, BC's glossy canvas is not IMO given the greatest QC, as one lot will have a bunch of flaw, or seeds etc. Crystalline, the BC glossy I am familiar will is OK, but due to globs and flaws etc. I only use it for prints where I don't have a large solid color. Not sure if their metallic has the same issues, but I figure it does.
Paul