My first attempt to combine kombucha and beer is underway. I used the same 2.5 oz of sugar (in this case pale malt extract)to 1 quart of water recipe that I use with standard kombucha, in addition I left the tea out. The tea is normally included partly for flavor and partly to provide a nutrient source to the yeast/bacteria because white sugar is pure sucrose. Malt is not a pure sugar so it should contain give the culture plenty of nutrition.
As you can see the culture (at the bottom) has grown quite large since the last photo I posted of it, and fermentation is generally visible within 24 hours of pitching.
It remains to be seen if the yeast and bacteria that make up the kombucha "mushroom" will be able to utilize the more complex maltose that makes up the bulk of malt extract. It will be about 2 weeks before I have a taste test for this one, but I am really looking forward to it. The next step will be to split the culture and try adding hops.