Bass Gnomes has released Crossmix VST, a simple VST plugin for mixing left and right stereo channels and more.
Crossmix delays each channel by 100 milliseconds, inverts the phase, and then mixes with the opposing channel to make your left channel play on the right side (as well as the right side audio), and your right channel play on the left (as well as the left side audio), but doesn’t turn your sound mono. Crossmix needs stereo content to provide any results. This can make your stereo mix sound “fuller”.
Crossmix is availableas freeware on Bass Gnomes.
More info: Crossmix VST – stereo shaper