King Arthur Flour offers a number of gluten-free mixes, for everything from
chocolate cake and truffle brownies to coffee cake, french bread and
gingerbread. They're a good resource for all kinds of cooking info, too. I'm sure you
can email them or log onto their forums to get more advice on rendering the cake
as egg- and yeast-free as well.

Here's the link:
http://www.kingarthurflour.com
and click Shop Online to get to their excellent catalogue.

(For the record, I have no connection to them; I just shop there a lot.)

Libby