[sdiy] Nice rubbery power cord source?

[John Speth]

My 1983 Prophet-5 is in great need of a new power cord. I'd like to 
replace it with a new cord that is just as nice. The characteristics I 
need are 3 conductor, black, 1/4 inch OD, a rubber (or rubber-like) 
cover, flexible, won't remember bends. I suspect I'll have trouble 
finding the rubber/flex features. Finding material specs, etc are 
impossible to locate. Can anyone recommend a source that might fit my needs?

Thanks - John