Z-Wave Dimmer Wiring in 3-Way Configuration
Well, I did a fair amount of investigating so I'll answer my own question here in case someone else comes across it in a search.

I have two switches.  A primary switch with a dimmer and a secondary switch.  The secondary switch has line, ground, and 2 travelers.  The primary switch has 2 travelers and load.

That's why the secondary switch has only one wire group coming in and the primary has 2.  One 12/2 is for the load and the other 12/2 has the travelers.

As for the ZWave switch for this configuration, there are myriad options.  I did get a ZWave dimmer in there repurposing one of the travelers to get line into the dimmer box from the secondary box.

This, unfortunately, precludes putting the secondary switch in.

Most ZWave secondary remotes I've seen require a neutral line which I don't have in the secondary box.

There are some ZWave remotes that don't require a neutral but they're often powered by a small trickle of current that can cause LEDs to light dimly or for fluorescent ballasts to flicker and be damaged.

I have a plan for how to update this wiring so that I can get both switches to operate again and I'll update this answer if I come up with something.