Welcome to the Land Cruiser Cult! My name is John and I am a life long member!
I would strongly agree that you stay away from V8 trucks. I built one myself and would rather have a stock Toyota. You are more likely to find a good running stock truck as 75+ percent of V8 swaps are poorly put together and over heat or they are well engineered and break stuff. Growing up my friend Jimmy Jones had a V8 Fj40 that ate transmissions and transfer cases as well as third members.
EDIT: Having said that, my next truck will likely have a V8...but that is a long story.
Get a Land Cruiser mechanic or club member to look at what ever you buy if possible.
http://canuckscruisers.com/ is down south of Raleigh.
I would be glad to check out any truck you can bring to me, I don't have time to travel and I am located in N. Raleigh. My fee is a cup of coffee

but your time would be well spent taking it to a pro. A good plan might be to get a local Cruiserhead to check it out for you and then take to a pro for a full look over - compression test, etc. There are club and TLCA members all over the state.
Don't just focus on 75 and newer, the best Fj40 I ever owned was a rust free 1972 that looked like it was just a few years old. I sold to a guy who became a close friend and he still drives it 15 years later. I also have owned a really clean 64 FJ45 and I 69 FJ40. I have regretted selling all of them. There is nothing wrong with the early trucks. You can upgrade the brakes pretty easily.
Most trucks are slathered with Bondo and a cheap paint job. I'd rather have a truck with a few rust bubbles and even some small rust holes in the factory paint that an Earl Schieb or Maaco special. The patina of a nice old truck is way cooler than a crappy restoration. This of course, is just my oppinion!
Some rust on a Fj40 is normal. It's like wrinkles on a 40 year old super model. Deal with it or be willing to spend a ton of money!
Enjoy the hunt!
-Stumbaugh