Hello James (that's my name as well), when you say you want to create a blog for SEO purposes are you talking about making a blog that will be Search Engine Optimized so as to rank highly on the Search Engines or, rather are you asking about creating a website explaining and teaching about SEO?
Certainly, you can do both. If you have SEO experience you certainly can set up a blog (and w/ seo experience can rank it highly) and even if you did not have actual experience with seo, you could rely on the teachings of others and pass along that information.
Hope it helps
(BTW, I find WP blogs hosted on one's own server to be the best over-all blogs)
