I've been tinkering with the ia-upload tool and incorporating Alex Brollo's better system of DjVu generation (better than converting from PDF, that is; instead it works from the original Jpeg2000 files and merges the OCR data in).
I've set up a test installation of the tool at http://tools.wmflabs.org/ia-upload/test/ and would love anyone to have a go at it, and to report any bugs at https://github.com/wikisource/ia-upload/issues
Because DjVu generation can take a while (quite a while if you've got a crappy slow laptop like me), the tool runs each job on the grid engine, starting every 5 minutes. The queue is shown on the homepage of the tool, with a status of each job. (Unless you're just re-using an existing DjVu file from the IA, in which case it's just uploaded directly to Commons while you wait, like the tool's always done.)
Thanks!