It would be really nice to have a single, self-contained file to make exchange easier.
I propose *.dsz extension which would just be a zipped up directory of the preset along with all the samples and images.
A zip file is really easy to read and can be pretty much treated like a folder. Many other applications use zip as a container. *.pak files form Quake series or MS Office files (*.docx, *.xlsx) are some of the examples of such usage.