This is a nice expansion. (Although it doesn’t solve the lack of Headers for Citation record creation and the Objects having SourceID instead of CitationID.)
Do you think that this Source field parsing code could be rolled into the built-in importer fairly easily?
After setting the delimiter configuration from comma to tab (in the CSVdialect option that Serge added to the parser), it becomes seamless to use the OS clipboard to copy from a spreadsheet and pipe the data into the Import Text gramplet.
To import a series of Sources would no longer require the tedious saving and then File Choosing of external files. You would just copy the cells (with Headers) in the spreadsheet, past into the Import Text gramplet and press the Import button.
Bulk entry is fairly familiar to spreadsheet users. Gramps would just need to distribute a spreadsheet workbook with the basic keywords headers laid out. And maybe have some example data.