Maybe you try to get a used powerbox here or in the german forum?
OVMS V2 is discontinued, but I think you also get it cheap when the V3 hits the shop
OVMS V3 is currently in beta.
But the current firmware versions are suficiently stable by now.
An order for 150 peces of the EU Version is on the way and will be available on FASTTECH within a few weeks.
With the OVMS you will not have a display or buttons, but a webserver via wifi, an app/server console via LTE or USB and soon also the SMS feature will be back.(Drive reports and charging status messages)
Bluetooth for the app is in planing.
And a realtime display with buttons like the Powerbox but via CANBus is in planing/testing to.
But could need a little longer, it´s also open source