I've been asked if I could create a version of M74 that used 2d6 instead of 1d20 so that the game could be played with six-sided dice only. This would be relatively easy to do. For example, the primary die roll would be 2d6 + modifiers with an 8 or higher indicating success.
Here's a combat example: a 3rd level Fighter attempting to hit a human bandit wearing light armor (+2 AC) would roll 2d6+1 (+2 for Physical Combat Bonus, + 1 for Fighter Bonus, -2 for opponents armor) and would hit on an 8 or higher. If the GM wanted to have keep the opponent's armor secret, the player would not subtract the armor and would just call out the result which the GM would compare to 8 plus the opponent's armor -- equal or greater would be a hit.
Saving throws could work as they do now except that 2d6 would be rolled instead of a D20. DCs would have to be lowered however -- exactly how much would require some testing. However, it might be better to redo the saving throw system to use the primary die roll mentioned above.
Other than a few minor details (like subtracting 10 from all the monster ACs), that's probably all the major system changes needed for a 2d6 variant of Microlite74. However, it would be tempting to rewrite the game to make the gam a bit more 2d6-centric. For example, attributes could be rolled on 2d6. An alternate/optional spell-casting method could be added where spells do not cost HP, but require a success roll to fire (2d6 plus caster level/2 minus spell level with an 8 or higher meaning the spell was cast successfully). Etc.
I don't see the need to produce an entire new version of M74 with just the basic changes needed to use 2d6 instead of a D20, although I might add a few paragraphs on how to do it to a future supplement. However, it might be fun to create a new game with the spells, monsters and style of M74 entirely based on a 2d6 system. I'll have to think about this.
[Don't forget that Original Dungeons and Dragons Goodies Are Available (for Cancer Fund Donors). Today (August 1, 2009) is the last day to make a donation and get in on the July 2009 giveaway. Thanks much to those who have donated -- and there have been quite a few of you.]