jpmanyhearts,

It is possible to get a two-element socket/bulb for the front parking lamps.
http://www.classicparts.com/1947-59-Double-Contact-Conversion-Kit/productinfo/47-905/#.VwJ65RMrIWo

It is possible to get a second rear tail/stop lamp.
http://www.classicparts.com/Taillamps/products/41/

Then, it is possible to wire-up those lamps to serve their original function and server as turn-indicator lamps.
http://www.stovebolt.com/techtips/turn_signal.htm

Also/or, as posted above by Jim, many people used to buy additional lamps for turn signals: front lamps on top of fenders or on the front valance/stone-shield, and rear lamps off the rear bedsides, etc.

fender mounted lamps on a truck
fender-mounted "pedestal" lamps

added rear lamp on a truck
rear lamps