1) I test combination of vMix and Mapio - it is software for mapping (www.visution.com). I can get video from vMix in Mapio as "DisplayX" or "vMix Video" over VLC, but this software support Spout technology - may be this way more faster ? And Mapio can work as FFGL plugin for Resolume and etc...
This combination is very interesting - i use vMix to manipulate content and Mapio to "mapping-rendering" it to my projectors and others
And if vMix can support FFGL plugins for outputs - its will be great.

I try many progs for VJ - part of this well used with external midi-keys, parts - good for precision scenario (play list), but vmix is better in usability when we dont know timing, and talent stuff.

2) In some VIP-project i need to use 2 videoservers to show contents to 3-4-5 projectors. I use proprietary software - it mapping, 3D-render (DirectX objects), get and show video in windows and other. This software runned in all servers and get sinchronization over LAN - main and backup server send video simultaneously. On outputs of this servers stand HDMI or DVI switch, and if main server hangs up - i simple switch projectors to backup server. May be create this algoritm in vMix ?