Finding a person passionate about sales is easy. Finding one that will buy into your vision will take some searching. You won't likely find this person through networking groups or an ad in the newspaper.
I recommend you start looking at postings on work websites (not job sites--you don't want employees, you want entrepreneurs). Depending on the age of person you're willing to work with, you may want to begin working with an intern from the local college. They will be a bit easier to mold towards your vision. I'm actually using interns now and they are very open to what knowledge and wisdom you have to offer. It's part of their degree work anyway.
You could work with head-hunters, but keep in mind, if they find you someone, you'll have to come up with some cash for the referral.
You could also utilize social media sites like LinkedIn, Facebook and Twitter to find someone. Looking through the niche groups for someone that is entrepreneurial-minded and has sales skills would work quite well. Once you get into the appropriate groups, start connecting with others that seem to have the same interests as you. Once you've developed a better relationship with them and you feel a good connection, then invite them to see what you're up to and begin the vetting process. This will help you find a viable partner--or you may even find multiple partners. Anything can happen once you go social.
You could attend local entrepreneurial events in your town, too. Anything is possible, it's really up to how much work you want to put into it.
Sometimes, it's better to hire an employee, pay them well and then offer them a partnership. By that time you know how they work they know what you're about and you may already complimentary styles. You'll just have to work out the agreements and they'll have to get used to being a part of the team.
Question added to topic Marketing • August 17, 2010
How can I find a business partner that's as passionate as I am?
I am a graphic designer with a unique business idea. I need a sales person, but I'd rather take on a partner with a sales background.