I made a "chewy chocolate freezer fudge" recipe for a relative with similar dietary concerns recently and it was very good. It had almond butter, maple syrup, cocoa powder, vanilla, salt, and coconut butter. It's from the book "Raw Food, Real World." Good luck--I had a really hard time tracking down a dessert recipe too. :)

Maybe a mousse or pudding with a base of silken tofu? I've made some with pumpkin and chocolate - basically just blending the tofu with the flavoring ingredient and some spices..

How about grilled fruit? Like pineapple? And use a little vanilla or ginger to spice it up. I think a beautiful bowl of berries with whipped cream/creme fraiche with vanilla (no sugar) would be nice.

I roast a lot of butternut squash and yams/sweet potatoes over the winter and find that they often satisfy me for dessert. She/you could also caramelize some apples and toss them with the roasted squash.

All those are great resources. I do gluten-free and mostly dairy-free baking all the time, though I usually use low amounts of regular sugars or honey. On the occasions I've needed to make things sugar-free as well, I've had good luck with just substituting spices and adding to the overall flavor, not the overall sweetness. Spices such as nutmeg, ginger, cinnamon, allspice, clove, and cardamom all can trick you into thinking something is sweet, even though it lacks sugar. Also, try using baking cocoa or very dark high-quality chocolate. With dense flavors like that, you won't even miss the sugar. Just be careful not to overdo the chocolate or it'll end up a little too strong!

Coconut is another ingredient that will add sweetness without adding sugar. There are some interesting gluten-free recipes out there using coconut flour. I've had the best luck when I use coconut flour in addition to a gluten-free flour mixture; it doesn't seem to always behave well used all by itself.

Concentrate on using the sweeter fresh fruits in bread or cake recipes: pears, oranges, bananas, berries, etc.

This idea is a bit off the wall, but could be fun for you and your friend. You could have a "flavor tripping party" using miracle fruit, so anything acidic would taste sweet. http://www.nytimes.com/2008/05/28/dining/28flavor.html?_r=1&scp=1&sq=miracle%20fruit&st=cse

Oops, I missed the sugar-free bit. Try this blog: http://gluten-dairy-sugarfree.com/ and this one: http://www.simplysugarandglutenfree.com/.

As far as a dessert fitting these guidelines, you might try making something with oranges or orange juice. If it's only sugar and sugar substitutes that aren't permitted, OJ or apple juice are great alternative sweeteners.

Another possibility: given that crepe batter has very little sugar in it, you could make crepes using unsweetened soy milk, eggs, GF flour, and vanilla, and stuff them with poached pears and whipped soy creamer. Not the most appealing to those of us without restrictions, but for your friend, I bet it would fit the bill.

Two blogs written by women with multiple limitations which might be helpful:
glutenfreegoddess.com
thedailydietribe.com
You might not find an exact match with so many exclusions, but you will find help, inspiration and support.
Simple things might help. For instance, a little vanilla can create the sweet message without sugar; if nuts and eggs are allowed, you can get inspired.
If soy is allowed, look for "unsweetened" where the ingredients are only soy and water -- it's as good as the soymilks with added sugar.

http://glutenfreegirl.blogspot.com/ is a great site for everything gluten free; http://cannelle-vanille.blogspot.com/ is a dessert blog, and right now she's gluten free too, so all her recipes are sans gluten (and look awesome!)

Here's a book:
http://www.amazon.com/gp/reader/1569757046/ref=sib_dp_pt#reader-link
Sugar-Free Gluten-Free Baking and Desserts: Recipes for Healthy and Delicious Cookies, Cakes, Muffins, Scones, Pies, Puddings, Breads and Pizzas