I used Doomchildren in one of my early DF games. This is a link to the chat log:
http://westmarchsaga.wikia.com/wiki/...y_Baron/Fourth
They blew up nicely, and it looks like there was a couple of incidences when a Doomchild died and took out a wounded one, and then the combined frags from two of them took out a third, and so forth.
The delvers got through mostly unscathed, aside from embarrassment, and a lightly armored Thief that got carved up pretty bad.