@roger,
brendalee treated me to lunch at Boston Pizza one day earlier this year.
I ordered the pierogi pizza. It was good in an odd way.
Thinly sliced potatoes, bacon, cheese, sauteed onions on a pizza crust. A thin schmear of some kind of creamy sauce. Sour cream on the side/top.
Interesting.
edit
someone else appears to have ordered it as well