I wonder how you'd run a campaign focused around monster hunting and or taming. Not that you wouldn't have other types of adventures. Now by "monsters" I mean the undead, magical beasts, the occasional dinosaur, demons, elementals, lycanthropes, the odd fair folk, giants and magical constructs. Mostly the idea is that you'd be hunting these creatures if they were hostile to human/demi-human/humanoid life, or you can go trophy hunting. You could even be hired to stock zoos or personal collections with some of them.
The second variation is commonly called the mon genre. Basically you get a little ankle bitter of a fantastic animal as a pet/lackey. It gains experience, grows and becomes a potent vassal of your's capable of routing entire regiments of trained soldiers. Of course, you can get even more of them and build a small army of these cuddly little horrors. Some of these monsters might even grow to twice human size.
You can even run a mix of the two with bands of heroes and their monstrous battling supernatural evil and kaiju. I'd use a combination of the two and run it with either Mutant Future or a MF/BECMI mix. By the way, the human/demi-human PCs are going to fight along side their pet monsters. So how would you handle either campaign style and what systems would you use?