Midnight -- loved this setting, but it has a specific set of requirements, so conversion to anything would be tough. Maybe a good gritty ruleset.
Dawnforge. Great setting, didn't get the attention it deserved. Cannot believe Eberron beat this in WoTC's design contest.
We aren't lobbying for a Midnight 4e, now are we?Bumpety bump, for more Midnight fans to come out of the shadows and speak up, if only in a whisper.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.