Here's an example of a deck built only from Core Set cards. It works nicely in casual play, but I can't say anything about its tournament worthiness.

The initial idea was to make the Cathouse see more use by concentrating on cards that have an activation cost. Amongst the Syndicate itself, there are quite a few, but not nearly enough to make Cathouse a strong contender in a monofaction deck. So what would be a nice complementing faction? Shub-Niggurath is the obvious answer, being a fertility goddess and all. Sacrificial rites behind the ... well, innocent is not quite the word I'm looking for ... worldly front of the red-light district?

So, without further ado, here's the whole deck:
2x Richard Upton Pickman (F 63)
3x Clover Club Bouncer (F 65)
3x Clover Club Torch Singer (F 66)
3x Patsy (F 70)
3x Extortionist (F 71)
3x Freelance Photographer (F 72)
2x Dutch Courage (F 73)
3x Cathouse (F 74)
2x Like a Moth (F 76)
2x Y’Golonac (F 122)
3x Priestess of Bubastis (F 123)
3x Slavering Gug (F 124)
3x Forest Sister (F 125)
2x Shadowed Woods (F 133)
2x Regeneration (F 136)
2x Burrowing Beneath (F 137)
2x Horrid Mutation (F 138)
2x Bred to Survive (F 139)
1x Shocking Transformation (F 140)
2x Gentleman’s Club (F 153)
2x Eldritch Nexus (F 154)