one of the things I have been playing with is mounting my look clipless cleat over the rubber sole of my neoprene booties.. I do this with a pair of old Lake road shoes with a single strap.. I can still flip the booties down out of the way and tighten the strap.. This eliminates the need to cut a hole for the cleat and leaves the shoes instead inside the booties when you remove them. No hole in sole means no air leaking in.. rubber sole between the cleat/pedal and the plastic shoe sole slows the transference of cold to your foot.. I'm still playin around but these are working well.. and are very warm..
Initially I had cut down the inner boots from and old set of rollerblades to fit the shoes into before they went into the booties.. but these made the fit too tight .. and too tight killed the circulation.. the absolute final fix would be to invest in the heated inner soles... but that's an investment I'm not ready to shell out yet..