Okay, I've actually found GNB1, and 5 working and was able to play them using DOSbox. On the other hand, all the copies I've found of GNB2-4 are basically inoperable no matter what I've tried.
I actually own a copy of 2, but it's in my dad's garage 30 minutes away and I really don't care to make the round trip at the moment.
I was so addicted to Silent Hunter I when I found GNB2. We had this old hole in the wall Game store in like '97 in Sellersburg, IN. They sold old games, and I saw GNB2 and just had to buy it for like $20 bucks. Never regretted it. Great game and series.
I would be immensely happy if someone took the game, made it 3D and just left the interface largely intact.