Just looking again at your idea, Beef. That could be even more interesting with skills at level up. You get to manually select their skills and then write them into the code. Death could simply land you in hospital and send you an e-mail stating such. Then you'd log on and see what went wrong and reprogram your pet.

I started working on one idea a while ago (and consequently got bored of it as I always do). You have a pet dragon which you enter into arena fights. Prize money is used to purchase spell components that will improve aspects of your dragon (speed, health, flame length, flame heat, agility, etc.). You never get to control your dragon - it fights on it's own. Perhaps this idea would work better Championship Manager style with a team of combatants, not just dragons? Then your units could support each other. Your characters never die, but you do have to pay medical bills.