I think that in general it is a very good idea, but it would require a fair amount of administration. Issues such as how long will items be left for display? and the like would have to be considered. Also the technical side of memory allocation and bandwidth and so on would need to be addressed.
I do, however, think that # of posts is a crummy way to determine if a person is allowed in. I don't post a whole lot, because I believe that unless what I say has some general appeal, I won't post, so as to avoid wasting peoples' time. I really don't care for posts that consist in their entirety of "LOL" or "How True" or "Good one!". I don't think that they really contribute to the community at large, but it still counts as a post.
So my vote is for yes, but it would still have a lot of question marks attached to it in terms of practicality.