There's a lot of variables here, and kevin403 hit on a big one.
When the wife green lights a possibility, it's just that... a possibility. Sticker shock will be your worst enemy in cases like this, so you need to assess what it is you really want and what you really need.
First question is what are your plans for the car? Are you wanting to do a full-on restoration, or just have it looking good for show or street use? If it is the former, you'll need to have the body stripped down to bare metal and start from scratch. If you just want the car to look good, then don't waste time and money having the car taken down to bare metal because it isn't necessary to achieve your goal. Another thing to consider here is body work. You may not think there's any bodywork to be done, but once your car has been stripped down to its naked glory, your P&B guy is going to turn up all kinds of warts, big and small, that you never knew existed, and that adds big $$$ to the equation fast!!! If the body looks acceptable to you now, don't strip it.
Second question is do you want to keep it 100% original, or do you want it the way you like it? If you really want a limelight green bird, and you're not worried about keeping the original color, then do the color change. If the decision is based on what color you like, then definitely do the color change because if you don't you won't be happy with the car in the future. You'll just keep obsessing about how you spent thousands of dollars on a paint job you really didn't want. Then you get the "well, you should have thought about that before..." lecture from the wife and who needs that?
Third question is how much work you want to pay for. Again, if your plans are to do this as part of a restoration, then the car should be disassembled. If your plan is just to make the car look good on the street, it's another waste of time and money to do this. Yes, there will be areas that don't get painted, but these will be areas that no one sees so why pay to paint areas that no one will know are painted unless they take the car apart?
Fourth question is how do you want the car painted? Do you want a factory-type enamel finish, or a modern, high-gloss, base/clear finish? A base/clear job will cost you about double what an enamel job will, but the finish on the base/clear is much nicer. If there's a decent place to splurge a bit, this is it.
The last question is finding someone to do the work. Personally, I don't go to commercial paint & body shops for two reasons. First, the focus of those operations is insurance-covered accident repairs. These guys get paid top dollar by insurance companies to do repairs, but the price of that income is they have to turn vehicles around in a timely manner so insurance work always takes priority over projects like yours, which is why it always takes so dang long to get them done. The second is overhead expenses. You're not only paying for the work but also for the lights, the rent, unemployment insurance, and every other cost the shop owner has, which drives up the per hour cost.
When I had my car painted (a 74 road runner with a color change from B5 blue to black), I decided to find a professional P&B guy who does work on the side, which meant I didn't have to wait on delays due to insurance work or pay for a lot of overhead. I found a guy on craigslist who had 16 years of P&B experience, did the body and prep work at his house, and used a relative's paint booth for the paint. I paid $2,200 for a full color change with a base/clear paint job, POR-15 primer to prevent any future rusting, and a fair amount of body work, which is about 1/4 what a shop would have charged me. It's not a 100 point show paint job, but I've shown my car at three car shows now and never heard a bad thing said about the paint and have gotten a ton of compliments on it. The down side of this approach is you have to find the right guy to do it, and there's risks if you pick the wrong one. Ask to see samples of his work and only pay up front for materials and you can minimize that risk.
So, what are the costs? If you want to do a strip and color change, you could be looking at $8k to $12k or more depending on what issues they find under the paint. If you want a color change without stripping the body, you're looking at $4k to $8k depending on what type of finish you want. Or you can be like me and shop smart and get the job done for $1k to $2k depending on how much body work needs to be done.
I would suggest you map out what you want, and what numbers the wife will consider without passing out from sticker shock, and go from there.
