And just an FYI but the SB6141 is now approved an available for retail purchase. It's a stand alone 8x4 D3 modem.
Great! Spec for spec it looks like the 6141 is almost exactly like the 6180 except for it has two 96mhz wide tuners instead of two 32mhz wide tuners and uses 12w of power instead of 8w.
I suspect this allows for the cable co's to be flexible with each set of 4 bonded downstream channels so they don't have to put them right in a line next to each other.