RVA, My Marshall 4x12 has this feature too in a sense. You can play it as all 4 speakers, or play it as 2x12.
4x12 Mono/Stereo Switching Facilities (1960A, 1960B, 1960AV & 1960BV).
To ensure maximum flexibility, four of our 4 x 12 cabinets boast a Mono/Stereo switching system on the back.
When ‘Stereo’ mode is selected, the cabinet is split into two 8 Ohm ‘halves’ for use with a stereo power amp
(e.g.: EL34 100/100, EL34 50/50, EL84 20/20, 8008 or VS 120/120) such as used in a rack system. When ‘Mono’ is
selected you are offered two different impedance inputs (4 Ohms or 16 Ohms) from which to choose.
Always
ensure you select the correct one to match the impedance of your amplifier and
NEVER
use both inputs at the same
time when the cabinet is in ‘Mono’ mode.
1) Mono/Stereo Selection Switch.
Selects either Stereo or Mono operation mode.
2) Right* input
When switch (1) is set to:
i) Stereo, this provides connection to the right* side pair of speakers.
Rated at 8 Ohms.
ii) Mono, this provides connection to all four speakers. Rated at 4 Ohms.
3) Left* Input
When switch (1) is set to:
i) Stereo, this provides connection to the left* side pair of speakers. Rated at 8 Ohms.
ii) Mono, this provides connection to all four speakers. Rated at 16 Ohms.
*Note:
No, we're not insane here! ‘Right’ & ‘Left’ here refers to the two stereo
sides of the cabinet as seen (and heard!) when facing the front of the cab.