This isn't really impossible. But basing on your side it is because this will require time and you have to make a name for yourself as a tech reviewer. Here's a few tips on how to get a review unit.

First you'll notice some big time tech reviewers are always getting a review models from manufacturers. This is because they are well known organizations and they already have viewers.

For Nokia. Motorola. etc... Having thier units avertised by different reviewers give them benefits. So in summary you can't just request a review model for your self desire.

So, to start to be a tech reviewer. You need to start in the buttom. Meaning start reviewing cellphone accessories. Companies that handles this kind of products are more likely to give you something to review.

The longer you review thier products. The more your audience will grow and your name will more likely be known. So. After you build your foundation. Try to contact the comapany that you desire to review.

Best regards