In the UK, I use Electrical Engineering Services 01204 884383
email (no web site). He does a range of cotton covered colours and sizes. I use mostly just black for my motorcycle restorations with his little coloured ID tags.
We also have Aoutosparks for classic wiring looms in any shape or colour
www.autosparks.co.uk/
I'm sure both these firms will ship overseas.
Ron