Here's a question I've been pondering for a while...
It's already been pointed out that there are few really good broadleaf examples of bunjin out there, and many of the ones I've seen (with the exception of ume bunjin) have been forced into a sort of "matsu-zukuri" traditional triangular crowned pine tree shape or a hyper stylized thin trunk with a tuft of foliage as a result of wabi-sabi philosophy. It's not just among Japanese, but Chinese penjing bunjin as well - although, at least with penjing, they go from [classical pine shape] to [completely abstract with very little formal structure] and everything in-between. As I understand it, this diversity in form is the result of different "schools" of penjing in China - some of which focus heavily on broadleaf species, and many of these seem to have a naturalistic slant in their styling.
So, being that we all know how we love rules/guidelines/styling conventions in bonsai, are there set guidelines for styling broadleaf bunjin NOT in a "classical pine form" or "wabi-sabi form", kinda like those ume and naturalistic penjing I mentioned above?