I agree with Akrisoner here. They don't make them like the used too! Also I have an 80's 2 stroke Evinrude 25 HP for my 14, the engine runs mint, there is more then enough new, aftermarket and used parts out there that finding something when I break it (*knock on wood*) will be easy.
That being said I agree with you that the used older motors are not cheap and the price can get up there, I spent $900 on my 25 HP. Best off to keep an eye on Kijiji or head up north and find a "Mom and Pop" marina or small engine shop. 90% that old guy working there has 10 motors out back he could sell you. My buddy father in law has a place like that on the 127 North of Bancroft. I got my boat and motor there and couldn't be happier.
Most of the older motors are pretty bullet proof too, for me that says it all.
Buying new does give you a full life for the motor but the way I look at it, the parts are more expensive when it does break down. But they are nice and shiny :0
2 Stroke over 4 stroke all the way, mixing fuel is easy and the engines are lighter.