Hi I spoke to Engineering about this, this morning.  The max size is indeed 180Mb and most people who've uploaded large files have been successful.  We don't really know why you had the problem you had.  It could be that somewhere along the line something timed out in the middle of your upload, but we don't know for sure.  We'll keep our eye on this, and run some experiments ourself to see if we can reproduce the problem you encountered, and if we find it we'll fix it.  Thank you very much for alerting us to this potential problem.