The actual point is, there's nothing magical in Neko/Miko which enables you to drop the keyboards the way you are here describing. That is, nothing more magical than can already be done with a "regular" mobile computer setup.
The same goes here as anywhere else: use the stuff that works best for you. Personally, I'm not fond of all in one solutions, especially when it's a hardware unit. When it comes time to upgrade or replace a certain aspect of a setup, I find time after time that it's much more painless if the system is modular instead of an all in one package.
This is especially true in the case of hardware fault. If you're pushing a deadline already, and a part of your system craps out, you can quickly find an emergency replacement for that one part if your system is modular, and send the faulty part back to the manufacturer/retailer in the mean time. If it's a single all in one unit you're working with, and a certain part fails, chances are you'll eventually need to send the whole unit.
(Of course, Openlabs might have this hinderance of an all in one unit cleverly solved in the Neko/Miko hardware design. Still, as I said, I'm personally wary of all-around products.)