I'm a software developer. Given enough time (which is actually saying given enough money) I can write anything. I can, for example, add enough code to LuxRender that it would read your Poser scene file exactly as is, with no exporter involved, much the way Vue does.

[Edit] I didn't notice your last question part until now - yes write a modified version of LuxRender. Since it is open source, that is pretty easy. Easier than writing an exporter, actually. The same is true of YafaRay - a modified version that correctly interprets Poser files is not out of the question.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)