I found out there are enough great settings so instead of creating a new one I decided to write sourcebook with additional rules and material to use in settings and games mentioned above. I realized that creating a new setting is too much work and making small details for existing settings would be more wise way to work this out.
I haven't published anything yet but I will use Google Documents for this. It is a good tool to share files and it can be edited easily.
What Is It?
It is a collection of my campaign ideas, places, monsters, NPCs, optional rules etc. to be used in my own campaigns and also to be used for everyone who wants to.
Where Is Grimworld?
Great thing in Dungeons & Dragons is that there are thousands of planes. Like Ravenloft you can get accidentally getting lost in mist or by purpose from special places players could get to some places of Grimworld (city example) from a portal or other disturbance between planes. Or GM could simply just include them in his campaign where ever he sees they fit best.
How To Use It?
There are optional rules (based on LotFP but fully compatible with other OSR and other fantasy games with small modification) GM can choose to use. There are also other setting things GM can grab and use in his own campaigns. Like NPCs, places etc.
What I Already Got?
Writing City of Nurmberg and adventure hooks there. Some additional races and character classes (less rules more details), optional magic rules for Elven and totally new magic rules what use power words instead of learned list of spells. Also I will include stuff from this blog in there.
Well, I will "publish" it freely at Google Documents when there are more material and will continue to edit it when I get more ideas. I don't know when it will be finished or will it be finished at all. It is a downloadable and viewable collection of my ideas and what I use in my campaign.