Dear,
I think , it's a good idea to implement this like some rapidshare or other hosting stuff use this method.
It's not a problem on IE or Firefox , it's more a problem in general way to manage files more than X GB,
there is limitation on proxy level also, during all tests, there is one proxy based on linux cutting the transfer a 2.00GB.
Even with firefox and the plugin download_them_all , i need to stop and restart the download manualy which is not user friendly.
Another comment about folder TAR ,i very a good idea but if i have 25GB (so big folders) on the folder, this would be nice to be disabled.
Have nice day