I'm not sure someone here has ever heard about bambookit, as it is quite rare. But it seems to be a very interesting XUL Motor, if I can believe the very few info available: http://www.componentsource.com/beaws/products/bambookit-gui/index.html
And a small example of Rich client here: http://www.devx.com/xml/Article/16704/0/page/2 But it seems that we can use it for web client as well.
Of course Bambookit website does not seem to be hosting anything anymore, but I hope that someone still owns an evaluation distribution to test this.
If anyone has any information about this, I would be glad to read it :-)
Thanks in advance and regards, S.