Answering my own message since i finally got a chance to test the upload process.
It seems that the upload limit in Share when using Adobe flash 9 or 10 is based on a signed 32-bit integer and therefore an upload is limited to 2GB.
The upload limit when just using the browser seems to allow ~4GB.
What is surprising in my test, was that upon attempting to upload a file which was 1.9042GB in size (on disk size reported by windows) flash 10 would see the file as a 2GB file and while it would upload the file based on the counter at 100% (under windows XP 32-bit client) after a few minutes the status would change to failed (though the progress bar remained green and showing 100%). The temp folder under tomcat has the file and the size (and md5sum) showed it uploaded fine but it would not show up in Share.
An upload of the same file without using flash in the ECM would work just fine.
I am going to assume that there will be no fix for Share until Adobe fixes flash to use a unsigned integer.
Hope this helps someone who hits this roadblock when trying to have users upload large files (any file 1.8GB or less works with flash).
