I'm about to build a pair using Rola (Plessey) 12" wide-range drivers. New old stock from Eric Cross at Vintage Audio World. Never used.
Design (and photo of an example build) is from JE Labs - I'll post mine when finished.
I'm anticipating a punchier sound than from my 8" Plesseys or my 6.5" brand not known (also supplied by Eric).