Is a Legacy PowerMaster available?

Another thought is that I could just get a CAB-1L Remote Controller for communicating directly with the TMCC PowerMaster for controlling locomotives in conventional mode. . .  Still, it seems like it would be cleanest to have the Legacy PowerMaster.

You may like to consider getting a TPC-300 or TPC-400 instead of using a Powermaster/Bridge combination. The TPC units will give you the option for conventional control through your Legacy system, and have several other benefits too. 

The Legacy Powermaster units should be available next year, but the prices are unknown at present.

A Lionel TPC unit is merely a "deluxe powermaster" and it works just fine with legacy. A TPC unit offers more "tunability" and will allow for conventional operation of MTH locos as well, even fire the coupler. IMO a TPC is overall a better quality component.

Yep, the TPC definitely looks like the way to do it!  When they call them TMCC TPCs, I had no idea that they worked with Legacy!  Thanks for the info!

that is because they were made before legacy and lionel just did not update paper work.

there is no date for release of the cab1-L and it will not be a cheap as we would like.

like above said use a TPC.  this is what I have, MTH Z1000, and a TPC and the legacy system.  no problems and I can run most everything.

Great!  Thanks to all the advice, I now have a TPC 300 en route.  Of course I had to purchase the 6-14191 Command Base Cable and the 6-14194 TPC Cable Set (for the PowerHouse), but this will definitely be a much more robust setup.