Resize aspect

[Simon Lord]

Hi all, I want to throw out the following question to see if anyone has 
a stack already done that can do the following...

My stack allows users to create a layout using template objects that 
fit the printed page.  However, some users don't have monitor that can 
display the full resolution, and 11 x 17 layouts are near impossible 
for most.

So I'm looking to make a stack that can resize all objects on a card 
*proportionally* to fit the new stack size (for example, a user wants 
to scale the stack down to 77% because that's all that fits on his 
viewable screen space).  But it will always be an aspect ratio 
proportionate to the layout they are working on.  That way when it 
comes time to print (or preview a print) I can scale everything to 
100%.

Or is there another way?

Sincerely,
Simon