I think the more realistic variation to the DX168X would be either a 2HE Rackmount 16 to 8 (Similar to a Midas DL16) which can be cascasedlike the curren version or a 3216 (like Midas DL32) but which is then not cascadeable due limitiation of the used protocol. A buildin DX Hub would be sugar on the to. The 2412 do not fit the used protocol well.
A GX2412 would be particularly nice to have as it would provide a 96khz option to the AR2412, while also allowing the ME system to work without requiring the SLink option card.