Just an anecdotal input on the subject:  In about 2000, I visited Redmond to get a demo flight in the IVP and ES.  I asked the demo pilots (forgot who the IVP pilot was) what they considered to be the shortest "reasonable" runway length for each plane.  The replies were 5,000 feet for the IV and 2,500 for the ES.  I bought the ES partially for that reason alone.  The ES demo pilot later came to his end trying to shoehorn a IVP onto a short, narrow runway.  I am happy with the capability of my ES and now fly from a 3800-ft runway at 7,000 feet elevation.  Landing isn't a problem but a gross weight takeoff on a warm, no-wind day just isn't possible.

Gary Casey