"It just seems rather strange to me, as on the other side of CG, in character artist forums like zbc, cgsociety, conceptart, polycount, etc, you usually see a lot more male characters than female, or at least it is much more balanced."

Well, to the extent that they're professionals, I imagine they work on what they're assigned. ArchViz, ads, films probably feature a greater number of males. Contrast that with casual or hobbyist users doing what they like, which for many (of both genders apparently) means predominantly female figures. After all the years that Poser has been around, I think that the gender ratio reflects something more fundamental than just a lack of enterprising vendors.

While there is probably some truth in the Field of Dreams theory, I think you can only drive the market so far. I just seriously doubt that many more people would render many more males if there were better male figures. 

There should be a ready made market amongst the folks who go gay themed art. I'd check out sites like maleposer and renderotica. You might get some ideas on what people would want in a new figure.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken