Maybe there is if divided between social challenges, exploration challenges, and whatever else is need to cover all activities. Mouse Guard comes close with its single conflict resolution mechanic, though I think I'd find that a bit sterile in D&D. Not to mention, I can't see D&D as a straight conflict resolution game. It almost has to be some form of task resolution to go with appropriate level of combat.
We say that climbers "conquer" mountains; I think tasks can be challenges/conflicts if they are a struggle to complete. And I think that, with the right degree of segregation and abstraction some engaging and tense conflict "mini-games" can be created for most conceivable challenges in D&D.
I think this could make a really blasting version of D&D, if done well, and I really do wish that this was where WotC were focussing their efforts.
The first is a DM who just doesn't want to make those hundreds of little permission decisions in the course of a night. Deciding Yay or Nay isn't fun for everyone. Rolling dice, consulting tables, letting the unexpected happen, based on chance and unexpected abilities. Rules in this case are a safety net. They exist to keep the DM grounded, to keep the game fair, and to help answer the questions that the whole group has. "What Do You Encounter" can be a fun question for the DM, too, after all.
The second group is the tactical players. Complex, involved rules are what this player thrives on, because they derive a sort of gearhead fun from tweaking the system and seeing where it goes, and even getting the most out of the system. There's a real fun in this mode of playing for a lot of people -- just look at everyone who enjoys 4e's combat system, which is this in spades.
This post described the cases where task-based (D&D/traditional RPG style) rules are useful really well. Where I disagree is that, for other cases, DM fiat is the best primary vehicle for in-play decision making - I don't think it is.
Several posters have talked about players "engaging" with the game play - I find this a trifle confusing, since players engage with the
game elements of 4E all the time, but this appears not to be what they are referring to. I
think what they mean is they want players to engage in (mentally) exploring the
imaginary game setting. Some have said that they want players to "
think like a character in the setting", which supports my belief, I think (brain hurts, now). I recognise this style of play; it's a fine option for a roleplaying campaign, even though I would not say that this style is, exclusively, what "roleplaying"
is (as some seem to claim). But, I don't think this style is best supported by DM fiat in place of rules - even in theory.
If the imagined setting has a "master copy" that resides in the head of one player (the DM/GM), what you are asking the other players to do is play the part of individuals who have a comparatively huge bandwidth of information available about the game world - typically, we may assume that they have all of the sensory information that the players have about the "real" world. And yet the non-GM
players have an incredibly narrow bandwidth of information available - generally only what the GM says and does. This is a fundamentally flawed construction.
To obtain the style of play desired, it seems to me that it would hold much more potential to focus on a few key aims:
1) Maximise the bandwidth where you can; shared drawings, written descriptions and miniatures setups and model representations could all be considered.
2) Remove or modify rules that do not contribute to the sharing of a congruent world vision. Rules that assist the players in understanding their characters, the world or other characters are fine, but things that do not relate to the world setting "reality" should be excised.
3) Give the players input to the world setting creation. To begin with, if they assume something about the setting that the GM did not, let it ride rather than contradicting them. Their imaginations have elaborated on the setting where the bandwidth of communication did not "fill in all the blanks" - let them fill that blank unless it causes problems more generally with the world. Further to this, invite player input to discuss how the game world "should" be. This mainly aims to use player expertise - either knowledge of foreign cultures or times, or logical thinking ability to spot where previously defined aspects of the game "reality" may clash with what is being proposed, or just creativity in coming up with neat ideas and concepts. Finally, when adjudicating the outcome of character actions, give the players a vote - literally. Remove the (natural) temptation to game the system/game the GM by making outcomes partly a matter of player choice. Make the exploration a game all present are participating in; relax your GM control a little, and see what magical places you can reach when everyone contributes to the emerging picture.
In summary, I recognise both styles of play [MENTION=2067]Kamikaze Midget[/MENTION] describes, but if I wanted to get to the one he claims is "non-rules focussed", I wouldn't start from D&D. I would still want rules - they would just be very different rules to those of "traditional" RPGs, and the role of "GM" would be very different, indeed.