The new QSI Titan comes in a version that plugs right into Bachmann engines with a 12 pin (on left) and a second multi-pin connector (on right) and another version with screw connectors.  The Titan has separate outputs (with lots of amp capacity) to drive a smoke generator AND a smoke fan (or both together using the smoke generator output.  This also has more than a dozen accessory outputs for lights or other stuff of your choice.  It hosts the Gwire receiver. 

It is also a sound unit.  It seems to me that there is no need for two decoders given the capabilities of the Titan.  The unit is available now.  Google it to see stores selling it.  It comes in 6 amp and 10 amp versions (double that output for short periods of time).  Con side:  It's expensive.

Checked out the Product list on the Bachmann web site.  The ON30 0-4-2 and 0-4-0 have totally disappeared, both w/o DCC, and the versions w DCC & Sound and DCC w/o Sound.  Has Bachmann decided to drop the product?

I have an 0-4-2 I was adding Sound & DCC to and was going to just buy the new one w DCC & Sound (easier) but ---- ?

Some vendors had been showing the 0-4-2 w DCC & SOund as pending release but no vendor received any.