Looking for simple piano scores in MuseScore format to use with a piano tutoring program.

Does anyone have some suggestions for some simple piano scores in MuseScore format (or MusicXML) of progressing difficulty to use with a piano tutoring program? The idea is to open the scores in MuseScore, export the MIDI files, which I can subsequently import into the piano tutoring program I am using and Bob's your uncle - a tutoring system that I have complete control over, with both sheet music and midi files. Unfortunately, I am unfamiliar with any sites that would have these files and my searches have not found anything systematic tutoring scores.

*A suggestion to the MuseScore site maintainers and users*
It would be useful if there was an area in the MuseScore sheet music section devoted to single instrument (particularly piano/keyboard) beginner scores for educational purposes. I don't know if there are any instrument tutoring programs that use a midi device connected to a computer other than piano, but if so a general "beginner" tutorial score section would be useful. Thanks in advance.