I've received a few questions regarding finding companies with XRF guns...so I thought I'd share my experiences:
1. try home/environmental inspectors (not necessarily labs) that look for lead in homes. They tend to have XRF guns since they are portable.
2. Call State or Fed EPA offices. They will be able to refer you to local labs that may own an XRF gun.
3. Band together with other companies (manufacturing and retail) to test. It will help to keep the costs down. Meet at one location and test all at the same time.
4. Rental companies: the ones that I've seen run about $400 per day with $200 shipping costs and $30,000 insurance. If you are grouping together to test this might not be a bad idea. It will keep the costs down.
5. Jennifer Taggert, thesmartmama.com, has an XRF gun and is testing for small companies. I think she charges $5 per component or $100 per hour. She's in LA so you'll have to ship your things there...she'll send them back if you pay for shipping.
In Denver we had a home inspection company come to a single location and tested about 30 companies at one time. Some were manufacturers, some were retailers.
I hope this helps!
Others who have tested please add your search/testing experiences