My son was "primary renter" in a rent-by-the-room house for several years. It worked well, and here's how:
1) Landlord designated a 'primary renter' on the lease - that renter was responsible for the entire month's recurring rent amount.
2) Primary renter, and other renters interviewed potential room mates to see if they fit in with the 'board game' / Video Game / LARP'er enthusiast community they had put together.
3) They had no problems finding renters from the local community college, game shops, LARP events, and from referrals from friends.
4) The Primary Renter paid the rent, then went back to his housemates to get their rent. Eventually, he tired of tracking people down, and required them to have automatic payments sent to his checking account. The house only had a problem with rent not being paid once (1x), and that renter was out by the end of the month, and replaced by someone who would abide by the house rules. There was another time when the check to the landlord (yes, physical check) didn't make it to the landlord's inbox on time, and the house was charged a late fee, and threatened with eviction. The landlord eventually found the check IN their mailbox stuck to some other mail, and withdrew these requests.
5) Yes, my son was eventually the primary renter - but only after 3 years of not being primary. My son found he didn't have the temperament to deal with the LANDLORD (the renters were all fine with each other), and eventually moved out to live with his girlfriend.
SO... it can work, but I have to agree with both neophyte, and waltworks - it really only works when the people know each other before renting together, and work out some rules vis-a-vie kitchen cleanup, laundry room & bathroom etiquette , etc.