I like the idea of additional bonuses for VIP's as at the earlier VIP levels im feeling little benefit other than additional monster slot and an auto play feature and also the additional training slots are yet another drain on my coins
id suggest maybe a multiplier system dependant on the floor you are currently on. Each floor gives the same rewards for fights/wheels etc for each respective map. but each floor you advance it adds a multiplier that boosts silver coins only.
for example;
floor 1 = 1x
floor 2 = 1.5x (or 2x for VIP)
floor 3 = 2x (or 3x for VIP)
floor 4 = 2.5x (or 4x for VIP)
floor 5 = 3x (or 5x for VIP)
that means for arguments sake a reward for Jungle-5 at floor 1 gives 200 coins (easy number) will give you 600 at floor 5 or 1000 if you were a VIP. or a reward of 1000 for barren land-1 will give 3000 (5000 for VIP)
maybe the numbers will need to be adjusted but this type of system gives a controllable increase that rewards players for advancing and fighting to stay on top (since you can get knocked down on floor 4/5) and even a further incentive for players to become VIP's.