In my opinion I believe there is sufficient traffic in this forum to justify a seperation for Plasma's.
I believe as the technology becomes more affordable it will also become a great deal more mainstream. The rate of products hitting the market and the speed that prices are dropping, it is an excellent time to make the seperation.
I think it's a great idea as a prospective plasma buyer would want to find out as much information as possible, about to make such a huge investment. Having a separate forum for plasma's would make it easy for people to get an overview of already raised topics.