Did we 3.5ify skill challenges yet?

[Noumenon]

I want a table of DCs for 3.5 that gives the same odds of success as the 4E DCs. I couldn't find one so I'm gonna talk out what I think so far.

In 4E, for first level, an Easy check is DC 5. You'll always succeed if you're trained and have +5; if you're untrained you probably have +2 and will succeed 90% of the time. Medium is DC 10, which is 90% if you're trained and have a +3 and 65% if you're untrained. Hard is DC 15 which is 65% trained and 40% untrained.

We want to simulate this for 3.5 characters. A "skilled" character can be one who maxes out the skill and has a +3 ability score bonus. "Unskilled" can't just mean someone with no skill points, because then the Easy DC stays at 5 through all 20 levels and they can never make the maximum. Perhaps we'll house-rule that everyone is considered to have all untrained skills as cross-class and maxed out, so an unskilled character gets at least +(level + 3)/2 to his checks.

So a first level skill challenge: "skilled" has +7, "unskilled" has +2.
Easy: DC 5, Medium: DC 9, Hard: DC 14.

A 9th level skill challenge: "skilled" has +14, "unskilled" has +8.
Easy: DC 11, Medium: DC 17, Hard: DC 22.

Complexity stays the same where you have to get 4, 6, 8, 10, and 12 successes before 3 failures.

Is that it? All I gotta do is fill out the table? Did someone else do this yet?

 

[Noumenon]

Followup:
In 4E, a 9th level challenge is Easy DC 8, Moderate 14, Hard 19. A skilled character has +9, unskilled has +4. So the chances of success are
Skilled - Unskilled
Easy: 100%, 85%.
Mod: 80%, 55%.
Hard: 55%, 30%.
So skill checks are about 10% harder for 9th level characters than 1st level.

One thing that doesn't work well is that my sorcerer has ranks in Concentration, Spellcraft, Knowledge (arcana) and Perform (dance). So basically it's Bluff or take his chances untrained.

But the nice thing about that is spellcasters always outshine everybody out of combat with their disguise self and suggestion and stuff. But in skill challenges, the monk with Tumble and the barbarian with Survival may be the best guys.

(I am letting people use up spells to get a +3 to their check, similar to the At Will blogger's "Powers of War" idea of letting people use up their dailies for bonuses. I love how that lets you use up your Scorching Burst to set a roof on fire for a diversion. It brings the daily powers back into creative roleplaying instead of only having uses in combat. You can use barbarian rage or monkish Slow Fall this way too.)