Wow!
I personally think that a new or used replacement bucket is in order here, however; you might find a sheetmetal shop who can make a repair panel or two for you if you look.
I know of a guy who could create the entire end tube and weld it all togeather to be better than new, I think it would be just as expensive as buying a new housing though.
I can not imagine that a fiberglass repair would be all that sucessfull. Fibreglass is wonderful stuff when used properly but I dont see it here.
I'm thinking that a split tubular repair panel welded to the outside may be the way to go. Then you could sand blast the inside and use a filler to re-create the inside surface.
This is a lot of work though. There must be a place to purchase used snowthrower parts somewhere. I'd spend some time looking before you try the repair.
Just my 2 cents worth.
Rifboy