We did this in our youth ministry at church. Believe it is a 100' - 125' run through the attic of our youth ministry building. I used Cat6 and the converters required two Cat6 cables. Works perfectly. Not sure what brand converter we are using.
Yep, I used this in a church setting as well. Output from the main worship PC to a HDMI splitter then to the auditorium projector as well as multiple TVs in the lobby. And it does take two Ethernet cables per run. Used the same as duder1982 suggested in the first link.