Go here they have 14, 16 and 18 gauge.
http://www.nyblimp.com/superior/wire.htm
You can also look for TQ products dragwire from the slot racing world. It looks small but has a thin insulator and is 16 gauge. I use it on my BRP SC18. !8th scale pan car. I got it here.
http://www.cyberslot.com/