The SLS might theoretically be able to put station components at EML2; an ISS or MIR major module is about 20,000kg, almost exactly the same as a full Orion stack.
The cost of supplying such a thing, however, would be horrendous if it is even possible. The payload of a given launcher to geosynchronous Earth orbit (GEO) is usually about a third of that to low Earth orbit (LEO). Surprisingly, EML2 is actually easier to get to than GEO, but not by a lot. Anyway, you need a lot more rocket to get a given mass there than the ISS.
Looks to me that the Dragon wet mass is greater than or about the same as the Falcon 9 payload to GEO. So, no cargo, if it's even possible. Soyuz is probably in the same category, or worse. So all existing supply systems would be able to deliver almost nothing to an EML2 station, if they could get there at all. The (still largely theoretical) Orion + SLS would be your only (and very expensive) vehicle.
Of course, a Dragon on a (less theoretical, but still unflown) Falcon 9 Heavy would have about the same cargo to GEO as the regular Falcon 9 to LEO, so it would be an option; it would cost 2-3 times as much for launcher than to the ISS. Getting the Dragon back to Earth would require extra fuel, however, which would cut into its cargo capacity, but if you just leave it there you could increase capacity by leaving off all the re-entry stuff. But if you can get a Dragon there, what's the point of the Orion? So probably Dragon wouldn't be allowed. "Not rated for deep space" or something.
Anyway, you're still going to be sending Orions there regularly, on $1B SLS boosters. And there's basically nothing to do there that can't be done at the ISS other than pretend to go somewhere else beyond LEO--so you might as well stay in the Orion. Thus, no space station, and no need for one.