Will there be an option to choose with/with out Controller or Motors?
The machine uses Nema 17s and the smoothie board. i guess we could create a bare bones version if you would like. but the nemas we have are hard to beat and smoothie board is a great micro controller. 
Do you offer a model that has the laser tube stationary?
Currently the only model is the FABkit.
It will have a moving tube,
It makes the whole system simpler; easy to align clean/maintain and reduces components, all together it provides an overall better experience and result.
The only down side is speed of vector engraving as the Y axis is slower due to a larger mass. However in terms of cutting the speed is limited more by the laser power than the machine. Furthermore when it comes to raster engraving is supper fast!
Also, what is the Max Length Laser Tube I can install.
The FABKit supports a Glass CO2 laser tube of up to 800mm length and 80mm diameter.