I have. I used to live in Canada, owned the same supra for 12 yrs now so when I moved to California I was determined to bring it with me.
First of all you'll need the title of course, from Ontario or wherever. Make sure the car is registered and licenced from Canada.
Secondly you contact Toyota Canada and tell them you need the proper paperwork showing that the car conforms to all US regulations. They'll give you paperwork that you take to the Customs agent, and also paperwork you have to fill out and send in to Toyota for their reference (for recalls, etc... and if you don't send it in, it doesn't get entered into the appropriate database and could hold up your customs paperwork).
So then once you have that in hand, you take it to Customs. I drove mine from Ontario, Canada to Detroit where I broke down (BHG) and towed it all the way to California LOL... but anyhow... when you cross the border DO NOT tell them you are importing the car into the US. If you do it right there at the border, it is such a pain in the ass. If your paperwork is not in perfect order they won't let you cross, or if the line is really long you could end up waiting hours, and if the guy is a real prick he may find something wrong with the car and refuse you entry into the US.
Also at the border if you tell them you're importing the car they'll make you pay taxes right on the spot based on the blue book value. I was lucky that my local customs and immigration office didn't even inspect the car or ask for any taxes/fees.
Just tell them at the border that "YOU'RE JUST VISITING" .... and if you are American with a US passport tell them you're just staying overnight to visit a friend or whatever. Don't tell them you're importing the car.
OK SO now you've got a registered, insured and licenced Canadian car into the US.
Take it to your local customs place once all the Toyota Canada paperwork is in order, and have them fill out their proper paperwork. Once it's in their database and they give you their paperwork, you take that to your local DMV and register the vehicle locally.
In California, it was a little of a pain because they had to send it to Sacramento and they took their sweet time, etc... so I had to get a temporary permit twice because they kept expiring, but eventually I got my title in the mail, my plates and everything.