Welcome to the forum!
Yes these guitars are rare, but they do show up on eBay & Craigslist and in local stores. You just have to keep searching and have cash ready to go!
Here's a great, recent PT-1 from Craigslist.
DaisyBat's PT-1 from CraigsList I would like to see his. I believe it might have an Alder body. If I had seen that one first...
I wouldn't get too hopeful about finding a PT-1 with a Rose. A few are out there, but Kramer had all the Rose's back then and we would buy at retail to use them. Big $$$ You'll see far more Advance Times with Roses. They were the hot sellers.
We built many guitars with stock Fenders, Mighty-Mites, Chopped Bigsbys, Floyd Roses, and Kahlers. Personally, I don't care for any tremolo. Well, unless you're Jeff Beck!
Chris