Actually, Carl has given out his speaker to many reviewers over they many years.
http://www.nolaspeakers.com/reviews_b.php
But people need to bear in mind that many established high-end audio companies, whether it be NOLA, etc., basically want reviewers with some credibility reviewing their products. Their position is that a review by a newbie does them no good. That's in contrast say to a new company who's eager to get their name on the map and will on the whole, lend their gear out anyone who will review their equipment. And HP and Carl go way, way back and obviously Carl still feels that a good review by HP will really help him sell his speakers.
Many years ago, I reviewed his first "mini" speaker, the Alon Adriannas, a real honey of a product, with a drop dead finish. The only problem with the Adrianna was they were ahead of their time; no one wanted to pay 10K mini speaker back in the late '90s IIRC.