Or, the question should probably be, what is the definition of "maid"? Yes, I did address this issue a little bit back when I started up Maid Runner, but I didn't cover all of the bases at that time.
First, in Japan, "maid" refers more to the costume than it does to the occupation. This is part of the reason why we also see "maid shampoo" and "maid reflex". It's not that these places are maid cafes, but rather that the female staff is wearing maid uniforms. Then, as part of the maid image, the female staff will also greet customers with variations on "welcome home master". Western writers (such as those at the Metropolis) will make a point of commenting on places with "maid" in the name as not really having maids. This misses the point. The idea is that various types of businesses want to cash in on the maid concept and therefore dress their female staff up as maids. It's not much different from McDonald's or Wendy's forcing their staff to wear coordinated uniforms and welcome their customers with formulaic greetings. The difference is that at a maid hair stylist, the staff is having more fun in the role than at a "normal" hair stylist.
If a maid cafe is a snack shop or restaurant where the servers dress up in maid uniforms, and "maid sham" is a hair dresser where the stylists dress up in maid outfits, what do we call a "maid cafe" where they don't use maid uniforms?
Specifically, places like MIA Cafe and Little TGV serve food (TGV is more of a bar, though), but MIA's staff dresses up in costumes from various TV anime shows, and TGV is a train-themed izakaya where the staff dresses up in train personnel uniforms. They're still grouped under the heading of "Maid Cafe" in the Akihabara directories, but they're really not maid cafes because they don't use maids uniforms. Instead, these places are generically called "cosplay cafes" or "cosplay clubs". I'd prefer to call them "theme shops" or "theme cafes", but within Japan the title used is "cosplay". Of course, there are cosplay bars as well, but I haven't encountered cosplay hair stylists yet.
Naturally, there's no reason to expect a strict division between the two types of shops. Many maid cafes have "cosplay events" where the staff dresses up as specific anime characters, or in other outfits (such as elf uniforms for Christmas). In the case of Mai:lish, from opening to 5 PM is "maid time", and from 5 PM to closing is "cosplay time".
We can muddy the waters further by introducing "butler" and "dansou" cafes, where "butler" generally refers to guys dressed up as butlers to cater to a female clientele, and "dansou" are women cross-dressing as butlers for the same customer base. While it's appropriate to lump these two (along with "little brother" cafes) in with cosplay cafes, it's probably a good idea to keep "maid" and "butler" separate largely because they are aimed at different target audiences. On top of which, I've yet to find a "butler hair stylist".
Now, why am I going on with this diatribe (other than the fact that I dislike the way the English press represents the entire maid movement)? Because I'm preparing to start up a multi-part blog entry on non-cafe maid-related businesses. My criteria is that the business follows the maid motif (uniform, greeting, treatment of the customers, etc.) As mentioned above, I haven't found many cosplay shops that aren't cafes, but if I do, I'll include them in the series. For the moment, I'll focus on Akihabara, simply to keep things under control. If anyone wants to talk about places in Ikebukuro, Yokohama, Osaka or elsewhere, please free to add a comment.