Download what you want, "Add to Queue" in Handbrake and then start it, walk away and come back and later they will be done. You could convert every single video on the website (might take awhile!) and only have to set the instructions once.

I know this doesn't replace the possibility for a built-in function on the website, but that might help you until something like that comes available.

I guess all I'm saying is you don't have to convert them individually, you just set it up once and add to queue and when you get everything you want you can start it up and it will convert them all for you. :)