Hiya...
I came across this problem before, where a client needed to upload an indeterminite number of images (up to 50) at a time.
Using HTML form uploading was not an option, because you can only upload one file per file input box.
The way I ended up doing it was getting the client to send a blank email with all the files as an attachment to a specified email address, and then the web page would actually connect to the mail server via POP3 and grab all the attachments and save them to the server.
I don't know if that helps in your situation at all... hopefully it does... 🙂
Unfortunately I can't give you the source code for it... you can have it, but I actually did it in ASP (red faced) - so it wouldn't be much good to you...
Cheers,
Matt