I did kind of create a mesh of both D20 Cthulhu and OGL Horror.
1) I took the character classes and creation from OGL Horror and added them to Call of Cthulhu, with a maximum HD limit for PCs. I arbitarily chose 3rd Level (from this point on extra HD are spent on Fear, Horror or Sanity Points or may be taken as endurance points to spend to increase certain skill rolls such as jump, running etc...).
2) I kept the Cthulhu sanity, and added an Int based one for Horror and a Charisma based one for fear, and use them just like sanity (Wis) in call of Cthulhu, but to deal with scenes of horror and how well the character holds up to being afraid.
3) Monsters and spells now do straight sanity, corpses and hacked up friends go on horror, and weirdness goes on fear. 5 points lost in one roll equals temp problem, and 20% in one hour equals some kind of permanent effect.
4) I use the magic from Call of Cthulhu d20 (I also created a huge list on non-mythos spells based on the ones listed in the Players Handbook, but toned down - but thats a side story).
5) Monsters work from Call of Cthulhu much better, as they tend to be i) very horrible ii) very dangerous iii) Sanity blasting....