Coconut milk, Raw young coconuts, Walnuts, lots of fresh fruits. Those are favorites with my 6 kids. I will make Coconut Super Food Cupcakes and they demolish those. avacados are another great source, I macke a chocolate pudding out of them and you could never tell its dairy free!
These hints are all really helpful, my son is underweight (has been since birth, he was preemie, growth restricted and had 'failure to thrive') and we have just been told by a hospital nutritionist that we need to feed him more full fat milk/cheese etc to fatten him up. We are not a vegetarian/vegan family (yet) but have always eaten a mix of 'regular' and 'vegetarian' foods, such as tofu (a firm favourite with the twins), soy and rice milks, etc. I would much rather be transitioning my son off dairy than giving him more. Hopefully he will gain some weight using your advice as well.