Legairre, your setup is certainly an interesting one, although I haven't experienced any problem with using a single sub to handle LFE and redirected lowest bass from all channels, including the surrounds. One point in your description is a bit unclear; you indicate that that there's a crossover to the surrounds, but if the internal sub(for the surround channel)crossover(actually just a low-pass filter)is the only mechanism being used then there is no crossover for the surrounds and they're being required to also carry the lowest bass.
