Hello, welcome to the forums!
I see that you like the classic bowie designs. I do too! Love 'em. From the ones you mention, I have the Laredo, it is a great knife for the price, fast, sleek, well balanced, feels good in the hand. Strong design and SK-5 steel is pretty decent for under $200.
Gil Hibben knives look great, but most of his mass produced knives are meant to be collected and looked at rather than used. (for the most part)
Not familiar with Downunder knives, but they look decent enough, maybe someone else here can chime in about them.
Oh, and you might want to check out Ontarios line of Bagwell reproductions. If they still have any for sale.
If your not dead set on a "classic western" design, there are a lot of other great bowies in your price range. Just say so if you are interested in any moddern designs too.
Just so you know, some of the guys here may give you crap for suggesting a large bowie for combat, but don't worry about it. You should try out knives that appeal to you, and bowies are a tested and proven design.