You're totally right! @lamogui was talking about a general-purpose bevel modifier that would work on any 3d model. That would be quite hard to implement and is the purpose of a 3d modeler, not of smode. What we indeed already have since 1 year+ in our internal issue system is this feature request of an option to make the corners of a cube rounded. Following your request, we gave one more priority point to this, but I can't tell you now when we'll find time for it.
It's quite beta-testing now, far from complete, and there is no short-term time allocated it, but if you wish to beta-test, we can send you a beta version. Just tell me!
CylinderVertexMask is our internal name (it corresponds to the C++ class name) for "Cylinder" 3d Mask. (Masks can be applied to nearly almost any 3d modifier to localize their effect). "Cylinder" and "Box" come in next version 7.4 which is planned for half february, but you might have it sooner thanks to a beta version. Note that "Sphere" 3d Masks already are there since version 6.*, so select vertices according to a sphere is already possible.
By the way, thank you your time answering to other users on the forum, that's really appreciable !!