Try [
harp.muse.pl] and [
harmonijka.mud.pl] I think those pages are the most popular harmonica sites in Poland. Ask the webmasters for a link exchange and I'm almost sure they will be eager to do it. If I were you i would tell them my vision of the site I create , the outcome i want to achieve and it's purpose and I would ask them for help, for tabs for making it more popular etc.
I believe the idea of inviting folks will work!
Best wishes!
Tomek N. (HarpSpirit)