<<Disclaimer: Verify this information before applying it to your situation.>>

Most of the respondents suggested calling Mr. Ritts in Philly. (215)627-3034 (www.mrritts.com or [log in to unmask]).

Here are some other suggestion:

Baskin Robbins ice cream birthday cakes are 100% GF.  I know how hard it is to go without flour cakes, but this is a good idea and everybody loves ice cream.  All their flavors, except for the obvious ones with cookies and stuff in them are GF.
 
I don't know if they'd ship to Boston, but in Minneapolis, MN, there is a co-op named The Wedge.  They do GF baking (cakes, bars, breads, etc.).  I called them about my daughters birthday cake - she wanted a "Dora the Explorer" character decoration.  I ended up doing cupcakes instead, but they were willing to try a Dora decoration - So, I'm guessing they should be able to handle a straight forward birthday cake.  They are on the web.  It might be worth checking into - good luck! 

use Danielle's Decadent chocolate cake (gluten free pantry) and Wilton's white icing and cake colors.

The "Gluten free pantry" makes cake mix in a bag. I find their products in
health food stores, Bread & Circus and online...

glutino.com...they have pre-made cakes that you can frost etc. 

Thanks for your suggestions. Tidings of Joy to All!
SusieQ

*Support summarization of posts, reply to the SENDER not the Celiac List*