Lowest beatable limit?

[Dazarath]

This issue has been on my mind for awhile and I was hoping someone could give me more insight on the subject. I've seen people say that any limit is beatable in a casino, while I've seen others say that 4/8 is lowest beatable limit, but it's a pointless grind. I understand that the skill level of the players changes things, as well as the rake. I wanted to focus mostly on the rake, because my roommate believes that 2/4 and probably 3/6 are not beatable because the rake is too high in proportion to the size of the bets.

Ok, this is the way I see it. Let's say at a 2/4 game, you win about 7% of your hands on average. We'll assume a $4 rake per hand, as that's what Commerce and Bay 101 run. So to break even, you need to earn 7 BB/100 in a game where there was no rake. I've seen a screenshot of a PP 0.50/1 database where a guy was running at 5 BB/100 over 100k hands. If we made the assumption that the Commerce 2/4 game plays like the PP 0.50/1 game, and we calculated how much 5 BB/100 comes out to be without the rake, it would be possible to estimate a guess at whether or not the 2/4 tables are beatable and for how much.

I understand that too many assumptions are made in this post, but I think it's a good starting point. As poker players, we're all looking for +EV situations, and it'd be nice to know that those of us playing small stakes are not fighting a losing battle against the rake.