I suppose it would taste like pizza on a flat biscuit. Not bad, but not what we're used to. Curious though...was the crust crumbly or did it hold together?
BTW, I love Bisquick dumplings! I tried making them from scratch once and they turned out like hockey pucks. Back to Bisquick!
When I want a quick little personal pizza, I'll use pita bread. They are just the right size and crisp up nicely in the oven. (Just don't leave them in too long.)
Every so often I make a pizza crust (yeasted) from scratch. And it's probably not unusual, but in more lazy, impatient moods I've made quick, small (maybe multiple) pizzas using store-bought breads such as chapatis, naan bread, or English muffins (a North-American cousin to crumpets).
Like debodun said, you can use anything you want for toppings.