We’re having the same issues. In our case it’s 16MB file. Our PHP.INI is already 64MB. This seems to be a gigantic issue and it doesn’t seem as if WordPress is fixing it anytime soon.
The .htaccess doesn’t work for me either. And there are about 1,900 posts which needs uploading so splitting isn’t an ideal solution at all. It would take several billable hours which isn’t good for anyone.
Can the Wordpres people PLEASE STEP IN and help us out?