I noticed that All Electronics (.com) have "Automotive Grade Power Cable" that takes up to 80°C. Product #'s WRB-18 through WRB-8 starting at 15 cents a foot for the 18 guage.
While we're on the subject, do certain types of connectors have their own limits? IE, could you use RCA connectors for your power hookups? I would guess that the connectors are around the range of the wire they hook up to.
I'd also like to use those monstrous (forget the name) 1/4" headphone plugs. You know, the ones that are (were?) used in midi keyboards and such.
So did the Cat 5 work ok then? Did you have to double up the strands? Would Cat 6 be any better for this (or just a waste of $)? Harbor Freight has some cheap wire as well: