I tried a feta and red pepper, wheat-free pizza last night which did not work due to lack of elasticity in the gluten free bread base. All my recipes are tomato free, as well as wheat-free.
An alternative is polenta pizza, made from cornmeal which is also wheat-free and I may use a more coarse instant polenta mix than for my polenta cake (see my last post).
One needs instant polenta, parmesan and the various toppings - feta, red pepper, stuffed green olives, red pepper pesto and herbs. The ideal is to have pots of oregano, basil and other herbs growing in the garden thus using fresh herbs for their flavour.
Here's a recipe from Good Housekeeping for polenta pizza.