I know LotRO has different fellowship sizes, full fellowship {6} and small fellowship {3}.I haven't spent too much time with LotRO, though, so I don't know how much small fellowship content there is.

EQ2 has a group size of 6, but they also have Mercenaries that you can fill out a group with. They aren't nearly as strong as real characters, but I believe they can be used successfully in non-heroics. EQ2 also has a couple different subscription options. The standard $15/mo unrestricted, the restricted Free to Play and a "Silver-level" less restricted plan for $5 a month. So if your systems can manage an extra account or two, you can use real toons instead of Mercs in a few spots.