The Future of the Friday Game

Well, it is getting to be time for a break from DMing the Friday night games, and while I have vowed to the guys that we are going to see their characters through to "god botherer" level.. around level 30.. after that, I am handing the game over to Robert to run a Star Wars campaign for five months, and after that, Gerwin will be running a Warhammer RPG for a few months, both of these systems and settings I am mad keen to try out.
Iain has said that once his Salushen campaign is completed, I can start my new campaign in the Tuesday night slot, with him taking it back when Gerwin's game is done and me shifting DMing duties back to good old Friday Night.

It gives me plenty of time to plan my new game.

Basically, the game centers on the city of Sigil (aka, City of Doors, The Cage).
Sigil is a unique, exotic location, a domain created and controlled by a mysterious entity known as The Lady of Pain.. she is the only real authority there, though there are many factions who would have you think otherwise.
Sigil is a city habitat that is connected to every other plane via doorways, gates and portals, all of which require keys.. and all the keys are different.
Because it connects so many different places, it is a truely diverse population that dwells there, and in the midst of them all are the player characters.

The characters are all members and new recruits to a mercenary group which has it's roots way back to when the Gith broke free of the Mind Flayers, in fact, the group is still mostly composed of Githzerai with an impressive mix of races comprizing the rest of the group.
Known simply as The Insiders, the group takes a wide range of jobs and sends members out on training runs to hone their skills.

What this translates into, is that during the game, the characters, who start at level 5 and can choose from a much wider selection of races than they normally would, are given selections of missions that they can do for set payment, or they can follow up on leads and go off on their own adventures.. as long as they maintain their obligations to The Insiders (after all, they get a lot of perks from being a part of the group, such as better prices on goods, regular work, the protection of their peers, etc).

Unlike my previous campaign, the focus is not the prime material plane (and the Forgotten Realms setting).. it is mainly about the wider cosmos, the politics of the various Factions at work in Sigil and beyond, and their own personal stories.
Because they will always have Sigil as a reliable home base, there is more scope for them to set up shop and background for themselves there.. who are they, what is their story?
Do they have family?
What do they want out of life?

Anyway.. I have started planning for it already (obviously) and already I am starting to create handy charts and tables for myself, to make the campaign a bit smoother and free flowing.

Here is a simple example...

Random Damage Type Table (for traps, spell effects, chaotic bursts, etc)
Roll D20
1-2 = Arcane
3-4 = Thunder
5-6 = Poison
7-8 = Force
9-10 = Acid
11-12 = Fire
13-14 = Cold
15-16 = Lightning
17-18 = Radiant
19 = Necrotic
20 = Psychic

I also have a nice map of Sigil, and plenty of ideas for how the Githzerai in The Insiders differ from their more jedi-like cousins.
For a start, they have what sounds like a Jamaican accent... why?
I dunno, it just seems to fit.