If I were you, I wouldn't do much to them except file off rough contours. Then consider a base coat of "chrome" on the bike and then a solid color, masking off the lugs and fork ends, rear stays, etc. A good powdercoater can do this. I've spoken with Groody Bros. in Kansas City, MO and they have done this to bikes. Takes more time and is a little more costly, but gives a nice look.

The "chrome" color is actually a metallic powdercoat and can be silver, gold, copper, etc. Lots of potential there for a unique scheme. Groody told me to be aware that is doesn't really look like true chrome, but is "chrome-like". It is very attractive, but some folks are disappointed because they thought it would look like real chrome.

I like your idea of pinstriping. Search pics of some older French and English bikes for ideas.

Good luck!