If you want to know where the best sushi pizza is in the city, I recommend Ni-Ji Sushi Japanese restaurant in Scarborough (my end of the city), located at 1095 Ellesmere Rd., M1P 2W9.
I've tried sushi pizza at multiple sushi spots in and around the city and Ni-Ji is by far the best I've ever tasted! Hands down. Yesterday, my boyfriend and I were craving sushi pizza from Ni-Ji and literally, that was all we order with a side of miso soup. No sashimi this time around, or spicy tuna rolls, or spicy salmon rolls, or tempura. Just straight sushi pizza's like real G's!
Aside from just their sushi pizza, the service is always good, the food comes quick and fresh, and the price is always right. If you don't believe me then perhaps you'll believe the hype: Urban Spoon rated Ni-Ji with 89%, Blog TO gave it 5 stars along with the title of being one of the best cheap sushi spots in Toronto, and Yelp gave it 4 stars.
If you're still a nonbeliever, then I suggest you trek your way east and give it a try for yourself. I promise you'll be saying I told you so!
Ps. They also do take-out and they're super quick with it. Perfect for a quiet night in. Order and call them: (416) 755-3335.