I really love the random NPC level chart from volume I of the Field Guide to Encounters and I am seriously considering trying something like it in my next World of Cinder outing. For starting PCs, no less! But there are two things I don't like about that chart. First, rolling d00000 is a terrible pain in the ass (and no, I'm not buying the special HackMaster crit dice) and second, a random table that hands out levels does not take into account wonky XP charts. I don't think it's fair that a Thief (xp to level two: 1,251) and an Elf (needs 4,065 for L2) both would have the same chances of starting out at high level. So here's a first stab at an alternative chart.
Random Starting XP Chart (d100)
01 - 0xp
02-09 - 2,100xp
10-27 - 4,200xp
28-63 - 8,400xp
64-81 - 16,800xp
82-90 - 33,600xp
91-95 - 67,200xp
96-98 - 135,000xp
99-00 - Roll again on Chart 2 below.
Random Starting XP Chart 2 (d100)
This chart lines up pretty closely with the Field Guide version, if you play a fighter. Basically, each step on the chart is +1 level if you play a fighter, with a couple of exceptions on chart 2 where you are actually 1xp short of leveling.
If I implemented this chart there would be one downside to starting with a big ol' pile of XPs. Characters that level up in play would be allowed to roll on something like the Mutant Future Experience Level Bonuses chart:
d100 roll - bonus
01-10 +1 damage in melee combat
11-20 +1 attack per round
21-00 +1 to a random ability (Str, Dex, Con, etc.)
So you might have a party with a wide level spread, but as the wimps catch up they will pick up some bonuses that the top dogs will not have.