I've broken screen (15") of my laptop (Medion WID 4000 Notebook pc (MD 41205) ) and I've a question. What does require replacement for this? Has it to be the same model or it only depends on size or resolution?
It has to be same size/aspect ratio (e.g. 15" square or widescreen), but apart from that, there isn't really any difference (unless your laptop is very old). (Just make sure you don't get a LED/different technology).
As for resolution, it doesn't have to be the same, but it is recommended.
The reason for this is that the cable that goes from the mainboard to the screen is pretty much the same as a standard VGA/DVI cable, you can have any resolution monitor but if the graphics card is not powerful enough for it, you may have problems.... But you may not, I have never had a problem in the few times I have increased resolution, I just know it is not recommended.
I think you would be hard pushed to find a economically viable replacement.
Personally, I would consider either using an external monitor with the laptop, or replacing it entirely / recycling it to be some sort of router or server.