In terms of single IP management for many devices, the options are:
- stacking,
- V400 as a Bridge Port Extender (IEEE 802.1BR) device that would be more like a 'dummy' 1U switch controlled entirely from your core and it can be stacked somehow (so with single 10G switch you can have many of those, linked via single or double 10G for example),
- network management system.
No such thing as VCS Fabric yet (dunno if there are any plans due to highly advanced NMS), and in Avaya SPB Fabric has different purpose and works differently, it's not a single IP management - for that you had to use Avaya/Extreme Fabric Orchestrator app which is to be functionally adopted by Extreme Management Center.