I'm in need of exactly 20 people to write a short testimonial on my site saying how much you liked this phone that I'm offering. You understand the dynamics and just give it a high praising and what not. Should be a decent sized length. But I will give each person $1 via paypal to take 1 minute out of their day to write one. Hit me up via PM and I'll send you the information.
You should at least let them use the phone so they can give honest testimonials. Otherwise, you're misleading your clients.