Well, for certain games, you can add a bit of variety and the unexpected by swapping out dice for a large dice type as a reward, even if that's not normally the mechanic. For example, take the two systems I'm really keen on just now, Mini Six and Shadow, Sword, & Spell. The use d6s and d12s exclusively, respectively, but I've developed "Bonus Cards", which can be drawn for various deeds such as good roleplaying or to mark a new campaign arc. These Bonus Cards can be redeemed to swap out the normal dice roll with varying dice. Here's a few examples, taken directly from the cards themselves:
-Replace Your 2D12 with 2D10 For Any One Roll (Shadow, Sword, & Spell).
-Replace A D6 With a D12 (Mini Six).
-Replace 2D12 Roll With Single D30 (Shadow, Sword, & Spell).
Does it sometimes skew the results and make rolls more unpredictable? Yes, but to me that's a feature, not a bug--and I like to tinker. And nothing hurts more than being up against the Big Bad Evil Guy, playing your bonus card to roll 2d12 instead of 2d6 and rolling...a sum total of 3.
I need to test it out in a longer campaign, but I really think this could be a good idea for keeping players involved in a system without quite as much wanderlust, as well as a chance to exercise their cool dice regardless of system.
Of course, this wouldn't work with percentile games such as Rolemaster, but Rolemaster has enough results range already, wouldn't you say? Thoughts?