If there's a product you want reviewed then the first thing you should do is contact the supplier or manufacturer and tell them that they should consider submitting a sample to RCModelReviews.com for review.
When enough people submit the same request, chances are that those suppliers who have confidence in their products will contact me and arrange for a review to be performed.
However, you can also start a thread in this forum and, if enough others support your nomination for review, I'll see what I can do to get my hands on one and cast an objective eye over it for you.
Remember, many manufacturers shower other sites and publications with free review products but they do so because they know that those reviews will undoubtedly be positive. Here at RCModelReviews however, if it's a bad product, I'll tell you.
So, if a supplier refuses to ante-up with a review sample for RCModelReviews, ask yourself why that might be.