Just confirmed it can be done with almond flour/meal. It isn't quite as good as the lupin flour, but put enough cinnamon and sweetener in it and you really won't care.

One other suggestion: after you've mixed it well, put more cinnamon and sugar-sub on top. I've been using Ideal Brown. Very good brown sugar sub, but you can do the same mixing a little molasses with erythritol, truvia, or something that isn't dextrose-based, like splenda.