Someone else has come up with a recipe that seems to work for a gumbo/etoufee, and another southener, too! She used Vital Wheat Gluten for the wheat flour portion of the classic roux.

http://www.lowcarbtransformation.co...highlight=gumbo

Take a look, it's interesting. I'll stick with the carbalose but there ARE alternatives using readily available ingredients.

ps: a quick google came up with this one in no time.
pps: gumbo file powder (sassafrass) is the traditional thickener, if my reading is right...no wheat flour roux required.