The last few years, I've been working as a cardiology tech, which, under our hospital, is under the umbrella of respiratory therapy.
Yes, it does only take 2 years. You don't even need a bachelor's degree - I believe you can do R.T. essentially out of high school. (Don't know if you need pre-req's first...). There are some plusses and minuses - depending on where you work. Some places, you're not going to be doing anything but giving inhaler treatments; at our hospital (Trauma 1), the level IV RT's would intubate, do arterial lines, etc.
The pay is not bad, (Expect $35/hr to start in CA) and 3 12-hour shifts a week is considered full time. But if your goal is to be a physician, you should stay on that route. Being an RT is a fine job, but it's not a profession as is being a doctor, IMHO. There is a gentleman on SDN who is fairly active in the forums who is an RT, and he should be able to tell you more.