Sticking the stripes on is bad enough - there are so many cars out there where the job was rushed and the stripes came out misaligned or wavy. It's hard to get away with just eyeballin' something with so much length involved (what might look good from the side, might be a "surfer's delight" when viewed from the front looking down the length of the stripes themselves). That's one of the main reasons (among a few others) I'm hesitant to put the stripes on mine (another being that mine was originally a 'no-stripe' car, and I hafta admit I kinda like it that way).
Getting a painter to duplicate the vinyl stripes in paint might be a tough deal, as not all painters are automatically masters of striping and/or graphics (for instance, my painter was awesome with the bodywork and laying down paint... but not so much with the graphics - I actually had to lay down my own TuTone hood stencil after he'd gotten it wrongly placed).
If your painter has the skills, the "eye" and ability to accurately duplicate the look, and you can afford it, you might consider having them pick up a set of stripes to use as an aid in making a stencil. Thanks to the advent of laser line indicators, there's no reason someone should have any problems getting their stripes straight, providing they take their time and do it right.
Good luck with it - make sure to post up pics. ::thumb::