I'll give a few guidelines for creating your own FF salad dressings,
 then a couple of samples that have worked well for me.  These recipes
 make dressing for two people.  Dressing is very forgiving, and if it
 tastes odd, it is easy enough to fix.
 Vinegar Base:
 I generally use balsamic vinegar as the base for salads when the rest
 of the meal is european-style.  For indian, middle eastern, and asian
 meals, I use brown rice vinegar, which I get at the local ethnic-food
 store. Otherwise, you can use apple cider vinegar.  I don't use white
 vinegar, since I like a little flavor with my acidic foods :-)  Start
 with about 1/4 cup of vinegar.
 Herb or Spice:
 If you want to use an herb, fresh ones are the best.  Otherwise,
 dried will do.  I tend to use herbs and spices traditionally used in
 the style of cuisine I am preparing.  Add a total of 1/2 to 1 tsp of
 herbs and spices.
 This is entirely optional, it just adds another dimension to the
 dressing. Use a flavorful sweetener, like honey (I've never tried
 brown rice syrup or malt sweetener, they'd probably be great).  Table
 sugar will add sweetness, but, like white vinegar, little flavor.  Use
 about 1/2 tsp of sweetener.
 This, again, is optional, but a nice touch.  Don't use yellow mustard.
 Stoneground and Dijon mustards are tasty.  Use sweet hot mustard in
 asian-style dressings.  Use about 1 tsp of prepared mustard.
 This will tone down the dressing a bit, if you like to dump a lot of
 dressing on your salad.  I generally don't add water, but then I only
 dribble a little dressing over each bowl.  The dressing is very
 flavor-saturated, so it actually will spread over two bowls of salad.
 Add about 1/4 cup of water if you want to use it.