My good co-op sells a lot of bulk, unsweetened shredded coconut. i get it a lot cause it's really cheap and is quite filling. anyways i've played with it for a lot of things. today i realized that you can essentially use it similar to a sauce thickener. most of the time i just chop onions really tiny and try to get them to soak up most of my sauces. The coconut shreds work well. i'm gonna try pulsing them in my spice grinder and see if, when smaller, they do a better job.
i am still gonna opt for onions and dark green leafy vegetables to soak most my sauce up, but this will help for certain situations.
i dont have a reference to it but ive seen (and tried) a technique a chef showed on tv once for thickening sauces with butter...
what you do is wait til the very end, turn the burner heat off, and take a nice chunk (ie. 1-2 tbsp) cold butter and whisk it in quite quickly.. it really does work tho i would be at a loss to explain why/how. try it tho.
"Butter can also be used as a thickener. When it is whisked into a hot liquid, the milk solids and proteins in butter form an emulsion that suspends the particles of fat in the liquid, creating a thicker, shinier sauce. The problem with this last method, however, is that you need lots of butter to make this work (1/2 cup of butter is needed per 1 cup of liquid--1/2 cup of butter is an entire stick!). "
I've tried every kind of low-carb, no-carb thickener known...You will not find anything better than Konjac Glucomannan...made from a root. You can read about it and order it here: http://www.konjacfoods.com/gum.htm. Just a very small amount thickens any heated liquid to an incredible degree. It has no taste whatsoever and contributes no calories.