Any chance Neato will offer a side brush upgrade kit?
There is no physical way to simply add side brush components to a Neato as an "upgrade kit". It requires a new case with holes for shafts etc., wiring connectors inside for the motor and so on, even different arrangement of internal parts to fit it in. When it is offered, it will be a new, and more expensive model. Adding an "upgrade" would not be much different than the DIY side brush in "Adding A Rotation Side Brush",http://www.robotreviews.com/chat/viewtopic.php?f=20&t=16078
It always bears repeating that side brushes do nothing on carpets; strictly for hard floors.
The additional power load of the motor also makes it more appropriate for LiOn higher capacity battery systems like the Vorwerk, and the additional motor noise may motivate their extra sound insulation. Those models go for twice the cost of a regular Neato (in the U.S.) and probably serve a more limited market.
As to the patents, there are any number of business reasons not to offer a more expensive unit with this feature (which doesn't even work on all floors), when building sales at start up. There are similar reasons why the feature would be restricted to a deal made with Kobold to sell an exclusive offering for their needs (an offer you can't refuse?). And you can already buy Dirt Devil (major brand) imitations of Roomba's in the U.S. replete with TWO side brushes. Take that you patent trolls.