I've been following development of modular robotics for years, The toy cubelets actually made me squeal, but this looks to have far more potential. I first heard about this sort of thing with the m-tran3 bots and I've been following the snake bots... If they have a custom "brain" unit to speed up the control of the rest, and some custom modules with various sensors and manipulators, this will be big. very big.
I think the way to speed it up would be to have the brain bot do evolutionary programming based on the number of modules it currently has, and switch modes based on that. So if it has six motion modules, and 3 non motion modules, it configures itself to its own internal model of that, and acts accordingly. If it loses a module, it reconfigures itself, ejects the non-responding module, and switches to a different logic tree based on THAT.
I love this stuff. I guarantee I'll be making a few of them once I get my tech shop running. Wonder how long it would take to print them out?