The limit on file size uploads is limited by a LOT more than just PHP. PHP has its limits, Apache has its limits, many web services have their own limits, and then you have the limit on the /tmp directory size which could be set by user permissions on a shared host. Not to mention just running out of hard drive space!
Your php.ini looks good, but as was already suggested- check the LimitRequestBody in Apache and make sure your web service allows this.
One common solution when you need to upload very large files is to use Flash or Java on the client-side since these have access to the client's actual file system. The Flash/Java can then break the file into small pieces which are sent one at a time and re-assembled on the server side. This has multiple benefits. First, you can resume broken downloads. Second, you don't have to worry about any scripts timing out. Third, it bypasses any possible file system limits that may be in play from PHP, Apache, web services, or other sources.