Tigerdude,
Yes, it's possible to resize plans both larger and smaller. Builders do it all the time. I personally have taken a few 40 size planes and enlarged the plans to make the 60 size planes (or even larger). The same process works in the other direction too, you can shrink the plans to make a smaller plane. But there are things that need to be taken into consideration. Many times structures are designed with specific sizes of wood for strength, and when you shrink the size of the wood the structure no longer is as strong as it's supposed to be. I'm not saying that you can't do what you want to do. But rather I'm saying that when you do shrink a plan down you need to have the experience to look at the plan and be able to tell if the structures of the plane will still have the strength that they need.

Something to think about.

Ken