Colorada51three-quarter,
No leg pulling in Windsor! They do (or did) make a 8 volt battery, and people did put them on the 6 volt rigs to get them going a little easier.
On Santa's list of the ten dumbest things to do to your rig, it might be real close to the top.
While easier to do than a full blown 12 volt swap, it doesn't get you much.
You will soon see people pop in to tell you a well maintained 6 volt system with all the proper sized cables is the cats meow!
Your original idea of the 12 volt generator is OK too, but better options exist unless you are trying to keep the old truck looking 'factory'.
Stuart