Last session of my Purana game (Mythic India using FATE3.0), I decided on using this die mechanic:

Roll two dice, one positive and one negative. 
If you gain a +5 or a -5, it counts as a +0, *unless* a Fate Point is spent. 

It works pretty well - it's fast, and it makes the +/-5 situations to be a little less common - though went they occur it ends up being a bigger deal!

While in the shower, I had another idea for a game that could translate over to DFRPG pretty nicely:  Nephilim, the Multisim/Chaosium RPG in which one plays eternally reincarnating spirits that possess human hosts over the course of history.

System-wise things match up okay.  Using Aspects to build your mortal character, and then having "Past Lives" be related to important previous reincarnation ("guest starring" other Nephilim in the troupe) would work out really well.

There is already the distinction between Spells (Evocation) and Alchemy/Summoning (Thamaturgy) in the system.  The elements match up okay with Nephilim's Ka Fields- earth, air, fire, and water, and moon as spirit/fifth element.  Nephilim has more elements, like Solar Ka, Orichalcum, and Black Moon Ka, but some of that can be handled as Aspected Magic of different flavors.

I'm likely going to start up a Dresden Files game set in Providence, RI (where I've lived for a while).  The city *begs* for it, especially considering the Lovecraft connections.  Being the small city in the smallest state, I'll probably expand it outwards, including Southeast New England and Boston in the works.

I'm also interested in doing something more exotic, like Calcutta (where my family is from), or Mexico City.  Both would require more work, as neither would really have "kosher" Dresden phenomenon.  Calcutta has a huge amount of supernatural lore, and considering the lifespan of wizards, you could even have some kind of White Council as neo-Imperialists who still remember the British Raj versus "upstart" local factions.  Mexico City of course would introduce the so called "Obsidian Court Vampires" - a fun fusion of mesoamerican deities and vampiric fun.