mamajama, my MIL is the same way. I was sick once and she came to "help". She just kept saying how terrible my house was until I got up and started cleaning!
At the moment, we live in just two rooms, one is for the boys and the other is our master bedroom/living space while we build the main room. It is really hard to have an entire household worth of junk stuffed into one small room and I often get frustrated. It´s like we are in a suspended state . . . always saying, "When the house is done, we´ll get organized."
I´m not convinced that will help, though. My mom always complained that she didn´t have enough space for everything. I come from a long line of pack rats, so maybe it´s inevitable!