we have a company here called TOWN & COUNTRY METALS. they are a nationwide dist. they sell aluminum and steel metal sheets in COLORS and only as 4 ft x 8 ft or 4 x 10 & 5 x 10 and some sell 024, 032 on rolls. i do a lot of signs like this of different sizes, none bigger the 12 x 18. i purchase the metal take it to someone with a 10' SHEER, have them cut as many as i need at sizes needed.....you need a 24 sq ft of a 32 sq ft sheet. and lookin in your area you got a bunch of metal supply places. and some of them will have a SHEER to custom cut their sheets.
NOTICE!!!!!
WHEN BUYING SHEET METAL...........before applying vinyl or paint, be sure to remove the CLEAR PLASTIC PROTECTIVE SHEET!!!!!!!!!