I've heard that DV doesnt look good when projected to the big screen.
But IF HDV is downrezzed to SD then projected would it look the same as DV?

I want to keep my work available for a large screen if need be, but I want to have a faster workflow of SD.

Anyone Know?

You could keep a backup of your HD for whenever you might need it, and make a proxy of it in SD for you to work on now and use for SD applications...

Cheers, Steven