First off, look into a SODA (Statement of Demonstrated Ability) for the color vision thing. If you can read a light-gun from an airplane, the FAA may give you a First Class.

There are certainly career CFI's, but there are a few problems with that. The obvious one is that all the young career pilots depress the pay scale...but an experienced CFI who specializes in one or more niche skills (Tailwheel, floats, specfic ME models, etc) can probably make $50K+, adjusted for locale.

The more lucrative paths for career CFIs are either to become a DPE (2 checkrides/day x $400+ = $$$) or work as a sim instructor for a big training company or airline. The DPE path generally requires that you stick to one locale, network with the other CFIs and Feds, build time, gain a reputation, then apply through the FSDO.

The big problem is liaibility... you (and everyone else in sight) will get sued if any student you ever touched is involved in a crash. Whether you did everything right or not is TOTALLY irrelevant...the plaintiff's attorney will hand-pick 12 morons who know nothing about aviation except what he's going to tell them ( well anybody knows that pilots are all reckless cowboys). This is OK for young time builders who own a 1988 Civic and a color TV...nobody will spend any real effort suing them. But if you have asssets and a good income...You will need insurance, probably an LLC, and you will want to be named additional insured on any owner's policy. See a lawyer about this.

Also, the question of aircraft maintenance comes into play...many CFIs join all of the local clubs to maximize their student base...a typical club may have airplanes owned by many different people, each of whom is responsible for their plane's upkeep. Well, not all of these owners do everything they are supposed to, and you may not have time to stay up-to-date on the logbooks of every airplane on the field (you are responsible for this...taking anyone's word for it is not good enough). The big risk here is flying a non-airworthy airplane and getting violated. This is largely avoidable if you own your own airplane or limit yourself to a few airplanes you know well.

Good Luck!