So I have built a cube, but before delving into that, first some background.
After collecting all the asylum packs and expansions (plus an extra arkham and two more core sets) I had a complete set of cards and started to build more and more competitive decks. There was just one problem with this, I haven't heard of any events for the game less than a 3 hour flight away, my friends only play the game sporadically (though a lot of them like it) and it is really not an easy game to play at high levels. So I found myself mostly playing four-way multiplayer with the centacle rules and monofaction highlander decks. This is not a big problem to me, since I find it almost more interesting than the extremely fast matches with competitive decks which are often decided by one bad play, one good card and which none of my friends really enjoy since they just like to play the game for kicks once in a while.
So, enter the cube. After reading about how fun magic players had with cube drafting I wanted to construct something similar for Cthulhu. There are of course some differences between the games, mainly manabase (in that Cthulhu doesn't use lands) and the number of factions (magic only has five). This means that magic drafts will be able to use a smaller card pool to construct decks (since decks will be at least 1/3 land and probably more). It also means that Cthulhu drafts will be more challenging when it comes to constructing decks that doesn't suffer to much from multifaction resourcing.
This is my cubes construction and the solution to the problem. I haven't tested it out yet but will hopefully get the chance next week:
50 cards of each faction (singles only)
80 neutral cards (singles only, no descendant since I don't like it)
20 conspiracies (singles only, I just like them, especially in multiplayer centacle)
Draft exactly like a normal booster draft (15 random cards per booster), but with 4 boosters per player instead of three. Then build a deck with 40 cards minimum. This will give you 60 cards to choose from so even with the amount of factions in cthulhu you should be able to build a deck that is mostly two-faction (with an option for a third colour as splash) and some neutrals as fillers (since there is double the amount of neutrals counting the conspiracies).
So that is that. If I manage to test it out I will make a short report here and if you want to know anything more about the cube just ask here and I will answer as best I can.