What is it that makes bacon so delicious? I am aware of many of things that bacon has going for it. It is high in fat, high in salt, and smoked.

But taking a potato, frying it, covering it in salt, and sprinkling on liquid smoke, does not taste like bacon. (Yes I've tried. I try liquid smoke on everything.)

So what is it that yields that characteristic bacony flavor? Obviously it can be isolated since there are a plethora of products that are marketed with a bacon flavor.
http://www.thinkgeek.com/brain/whereisit.cgi?t=bacon&amp;x=0&amp;y=0

How can I impart some quantity of beautiful bacony flavor to other dishes while avoiding all the saturated fat and nitrates? I am asking specifically about isolating the flavor- not more healthy bacon substitutes.
The big missing thing in your description (fat, salt, smoke) is umami. You can see this in bacon-flavored products. For example, bacon salt (click on a "nutritional info" link) contains monosodium glutamate.

So if you want to make something bacon-flavored, short of using bacon (and possibly draining away a lot of fat), you're generally going to be looking for source of umami; see "What foods are high in umami?" or "What is a good vegetarian source of umami flavour?".

Also, bacon is definitely not acidic, and perhaps slightly sweet. This means, for example, tomatoes are probably not a good way to get the umami, and that whatever you do, you might try adding a tiny touch of sugar to bring out the flavor a little more. Things like shitake mushrooms and nori seem like better flavor matches. (If you've had furikake this shouldn't be too surprising.)