So, the difference between a rogue 3 and a rogue 9:
level 5 daily, level 9 daily
level 7 encounter
level 6 utility
Compare that to what you might gain from the other class. Especially in the case of the damage features (sneak attack, quarry) it'll be worth doing for many, many classes, just dip 1 level and move on.
Even if the example character traded those 4 powers for, say, 2 at-wills, 2 encounter 1s, and 2 daily 1s... and no features at all... he'd probably still be doing fairly well for himself.
I'm not trying to dissuade you from seeking a solution, but I think it'd be easier to, say, make a Spellthief class.
Anyhow, trying to consider it more seriously, let's say that you were able to swap out power slots and features for the new class's, and they were set in tiers so you knew what you needed to trade.
So, for example, if you know that Sneak Attack and Quarry are the same tier and you could swap one for the other, that's all well and good. Maybe you can get Cantrips by sacrificing a utility power or whatever.
Let feats invested get you the very minor class features, like the ability to dual wield non-off hand weapons... should have some way to get a bonus at-will from each class.
So you might look like (after a few feats spent), 3 rogue / 3 ranger / 3 wizard
3 Daily (usually 1/5/9, but restricted to all level 1 cause of max class 3, divvied as desired)
3 Encounter (usually 1/3/7, but restricted to 1 or 3, so probably 1 1, 2 3s)
2 Utility (usually 2/6, but restricted to 2 2s)
4 At-Will (at least 1 from each, so like thunderwave, twin strike, deft strike, piercing strike)
Ranger Two-Weapon Fighting
Quarry
Rogue Weapon Tactics
Cantrips
Or somesuch.