Other options, include:
Android device with voxwav... I am not sure you can leave this on all time
Wireless (high end mics)... The issue is price, but eBay can mitigate this
Another PC running second VC
Personally after lots of research I decided to go with wired solution, and multi conferencing mixer for the following:
1. Noise cancellation, echo cancellation, gates ...etc.
2. I am able to know where voice command originated ... Hence, commands like lights on will work based on which room I am
3. One PC and on VC is easier to maintain
4. I got the mixer dirt cheap on eBay + a very good deal on 4 boundary mics (whole thing for 80$)