rehashed, but hasn't been mentioned in a while....
Today you need to sit down at your computer and find any supplier or vendor you work with thqt you can talk to. Call them up and tell them you would like to give them a glowing testimonial for their website - you love their product that much. Ask them for a mention of your website, since you'd like some promotion as well.
Easy if they've already got a testimonials section, even better if they don't and you get the first and maybe only link.
Now, here's a flip side idea. A friend of mine wants raving good testimonials, in a market that's SEO heavy. He publishes a testimonial page with links - with the intention that people will write glowing testimonials in exchange for a link. I've written one myself :). He publishes your testimonial along with a link on his very authoritative page. He gets a lot of testimonials from big sites in the industry :).