Long-form video encoding for YouTube

Hi,

I have 2 long-form videos I need to render and upload to YouTube but if I follow the methods usually applied to 2-3 minute videos I end up with enormous files. I am wondering if anyone knows of any other way's/codecs this can be done?

For example @ h.264

1 x 30 minute 1080p 25fps @ h.264 16mbps = 3501MB
1 x 4.5 hour 720p 25fps @ h.264 6mbps = 12349MB

I can't really lower the bitrate any further because the pixelation becomes very apparent. So am I stuck with these? Does YouTube even allow files this big to be uploaded?!

Any advice would be greatly appreciated!