Martin, you are on the right track in your ideas. Using a draw pipe will greatly reduce the volume of water that the air could otherwise move, but if you put a bell in your pipe where the diffuser will be placed, and the diffuser is at least 8 feet (3 meters is better), you can maximize what water can potentially be lifted by the air.

Diffusers need at least 8 foot of depth to create adequate water lift and circulation, so you will need those bubbles confined in your pipe at least that long to create lift within the pipe.

An excellent setup that I found was using a 36" diameter (1 meter) pipe resting 12 inches off the bottom on stands, with the top of the large pipe 15 feet (4-5 meters) under the surface. The diffuser was placed in the top of the pipe and a tapered bell was made to attach a 10 foot long, 12 inch diameter pipe centered directly over the diffuser. The tapered adaptor was 2 feet tall. I was surprised at the volume of water lifted with a fairly small volume of air being used.

It takes accurate mapping your pond bottom and exact depths, plus a lot of labor making each stack-lift, but can definitely be done!

Rather than using one large compressor, I would suggest using a few smaller air compressors and placing them closer to where your diffusers will be placed.

Depending on where your deepest areas are, you may only have to aerate the deepest points to use fewer diffusers and less air/electricity. I would expect an entire system to run about $30,000 USD, but your labor, materials and equipment costs may be considerably lower than here in the states