1) You generally what type of paper used to print the covers? What do you recommend?
2) What do you use to cut with precision the paper? There are sheets of paper with the size already suitable for DVD covers?
3) So it is possible to request the creation of some cover missing here?
1) See this post for my paper recommendations. Ignore the babble about other covers. =)
2) I use a standard paper cutter but scissors work just fine since the cover edge is easily followed during the cutting process and slight variation in the straightness of the cut are not really visible once the game cover is inserted into the cover.
3) I can't speak for others but in general . . yes you can request covers. I only made covers for games sold by GOG but did make a few special requests. BangHowdy seems to be the only community member that is actively making covers so direct your request to him. I would suggest that you don't request a cover every time a game is released as they are usually made by whomever is working on covers ASAP after release. Requesting a cover for every release is usually not necessary since it's usually on the "things to do" list of whomever is actively making covers. =)
Hope this helps