I've had good results modifying the 'quick oil bar' in the Joy of Preparation.
If you have the script, make all of the usual substitutions: applesauce for
oil, defatted cocoa for cocoa, ener-g egg replacer for egg. To make it
really chocolatey, I halve the sugar total, add an spare 1/4-1/2 c. of
cocoa. I usually double the recipe because my housemates can snarf the
whole cake in 12 hours (which acts as a major control on *my* consumption
:-) . If you don't have the script, and want the recipe, let me know and I'll
write one up and post it.

For icing, I just mix up a little rice milk, cocoa, and powdered sugar
and make a sugarcoat, and pour it on the warm cake so it soaks in xcvii.