Remember that a 15 gallon BOIL in a keggle will only yield about a 13.5 gallon batch due to boil off.
That said, you could pull off about a 13.5 gallon batch in a keggle if you used some fermcap to control the boil off just a bit.
Primary #1 - Midnight Ryeder (Midnight Wheat and Rye)
Primary #2 - Florida Weiss
Primary #3 - Kane-DOH APA (Honey Citra APA)
Secondary #1 - Downtown Flanders Brown (brewed August 2012)
Keg #1 - Raspberry Florida Weiss
Keg #2 - Cinnamon Raisin Cider
Keg #3 - NONE!
Bottled - NONE!