I want to outsource foreign language SEO work to SEO suppliers in various countries. I've had a few thoughts about how to recruit potential SEO suppliers.
1. Look at SERPS in regional Googles (country extension) for competitive phrases, like seo, search engine optimization, etc and contact those that are ranking high (should be a strong indication that they know what they're doing)
2. Invite proposals from organisations like SEMPO (send a project brief to SEMPO members, tailored for suppliers in different countries)
3. Run a PPC campaign in each country, with a landing page describing the job in detail.
Are there any other better methods I could use, and what do you think of the ones I've mentioned here?
I'd say your first strategy (#1) is the best bet. There's always elance.com, but that is such a mixed bag. You can always submit a project there and request proof of first page SERPs for keywords/phrases you define.