As the willie engines are pretty expensive (same for the megane engine) What are the options? Is it possible to use a 1.8 16v head on a 2.0 8v 440 engine? I heard something about a diesel crankshaft, but it doesn't make a 2000cc?

for a secondhand 2.0 16v engine, about €1000 is a normal price. The 1.8's 16v are almost for free, and the 2.0 8valvers too.

Thanks

8 valve and 16v blocks are a bit different. 16v blocks have one oil channel more than 8v if i remember right.

Why not search some lightly crashed car or whitout MOT? Often whole car is only bit expensive than just engine and you can sell rest of car in parts.

You basically want the megane F7R bottom end with a 1.8 head and 33mm megane valves.
If you are serious about one drop me a PM i may b e able to source an engine for you.
16v head would go on an 8v bottom end if you had 2 polates welded into the water jacet on the head, as this overhangs the 8v block
Adam