I checked most of them by my discussion page, or by some random edit from the RC list:
http://encyklopedia.servis.pl/wiki/ http://www.eldamar.my.link.pl/encyklopedia/ http://www.wiki.brief-reklama.pl/ http://www.artemobili.com.pl/encyklopedia/ http://wiki.optymalizacja.com/wiki/ http://www.polsek.org.pl/Main_Page.pyw (all the links go to the Polish Wikipedia, but anything you insert in the URL works) http://www.ee.pw.edu.pl/~kochanor/wiki/ (not the Polish Wikipedia, but other Polish projects)