I have a 5speed turbo you could buy...
But the trip out here and the drive home might be a bit much, not to mention getting it over the border!
Really it comes down to what you want to do with the car.
I always advise folks to buy someone else's project. You'll never get your money back out of a hot rod... so why not let someone else not get their money back? Put together 12-15k, and wait for the next guy on
http://gtepowered.com/ to decide he's selling the car. My 2J car is way further along the path of 'mint' than my 7M car, and it cost me less. A lot less. The difference? I built the 7M car, and I bought the 2J car from someone else already complete. I've seen 5 or 6 high end cars sell over the years, so one comes up every year or so.
If you decide to go the other route, and buy and build your own, get a digital camera, an AAA membership, and post here with detailed pictures before you do anything. (Including buying the car in the first place!) The AAA group will do a detailed inspection for you prior to purchasing the car for cheap. We can tell you how to fix pretty much anything, and what to look out for. Just for example, you should get any head checked for hardness before spending a dime on it. They tend to anneal over time, and if a used head isn't hard anymore, it's worthless.
There's nothing wrong with the NA chassis - there's been a few folks that do full turbo swaps over the years. DrJonez was one such, and he's based out of Detroit, although I don't know if he still does these or not. Actually, there's no difference between the actual chassis - only the engine, transmission, electronics, and sometimes the rear end. In many places in the US, the NA chassis means cheaper insurance, too.