Are you sure you want a "new" front derailleur? The list given above would be used, most likely off of eBay. They would be better than any new 7 speed front derailleur.
If you have an old mountain bike derailleur that might work as well. I'm running an XTR 910 on a triple 7 speed setup on my road bike. However, my large chainring is only a 46t.
John