It is a GOAC. Don't worry, it will have a cart slot.
I am actually making two of them, one is probably going to be months before I finish, since I lack some important parts (I would buy them, but they appear to not exist), but this current one pretty much has to be finished ASAP. Already have the mobo all working, back of the case is 90% done, front of the case is 50% or so. After that, just need to wire all of it together.