Noisebud has released Leaky2 as VST2 and VST3 plug-ins for Windows and AU for Mac.
In version 2 of Leaky, you can choose what to leak, you can switch between L, R, Sum or Difference. The destination is no longer locked to the Sum/Mid, you can now leak into L, R, Sum or Difference. You can also switch between 3 modes, Leak, Move and Replace which makes it easier to handle phase cancelation errors.
Price: $29 or if you donate before October 28 you'll have a 40% discount with the code Leaky2intro.