Nice collection Guillaume, I have about the same with Lego...except they are all open save for one Millennium Falcon still MISB.

Something I have been toying around with has been developing a DSM through Lego's "Designed by Me" program. It is a CAD program with all the bricks and you essentially build something in the program and it automatically produces a part list and instructions, then you can order the model from Lego. The neat thing is you can then share that model with people and they can order it as well. Per piece count, it about an extra 15-25% in cost than a mass produced set, totally worth it for model I was able to build. When I get the car back together, I'll make it my summer project designing one that can be bought from Lego. Just need to get the scale right and figure out how much detail to go into.