Vinyl Studio will import flac files with DoP content and then allow you to write them out to DSF files. It is meant for manipulating files digitized from vinyl, but you can act like your DoP files are individual digitized tracks. You basically tell it you want to import a group of files and it will import them and split them into tracks. There is an option to set the track names according to the file names. You may have to specify the track file name format, depending on your naming convention. You may have to do some manual tagging, since it is expecting a raw recording file, not one with lots of tags. You can set tags for the album or for individual files. You then save the tracks as dsf files, at the same sample rate as the original files. It is really not meant as this type of conversion program but I think it will work.
I tried one file and it seemed to work, assuming I did it correctly. It was a quick trial so I am nor sure if their are any potential problems or quality issues. There is a learning curve with the program, but since all you are doing is importing and saving it should not be too bad.
In general, VS is a very good program, but it was not really set up for this type of conversion. There is a trial version available and the cost is only $29 to buy.
It may take a little time, but is at least a potential option. If you go that route, I can help you if you have any questions with the program.