The Rec Guides are actually where this has sprung up from.
I realise that.
What I mean is, take the Marauder for example, the following have a large and small gun in each arm and a mediumish gun in the torso:
1R, 2R, 3D*, 3L, 3M, 3R, 5L*, 5M*, 5R, 5S*, 5T, 7D, 9S*, 9W*, 9W2*, C
The ones with *s have a larger or energy torso gun, but everything else fits.