Time, distance and any acting ability are 3 things I would not have enough of. A shorter promo video, rather than full length film, would be more likely - but not likely for me this year.
True on that Sir James, time would be a problem unless managed well by a consistent and up to date schedule. Or why one of us film with someone else and the others do the same, we send a copy of the film to the person who will collect it and put it together into a combined film and there you have it.
Distance is also a problem, but if it is filmed by someone who knows an ideal location and send the copy to the film editor, that should be no problem.
Acting ability, I can act but in regards to others, all I can say is why not have fun? Why not act like in the Knights in cinema (why not Sir Edward re-enact Sir Balian or Sir Nathan re-enact as a Teutonic Knight with an Aragorn attitude or persona, or why not Sir Brian be the "Green Knight" from the poem, or I could be a "Renaissance Knight" like Don Giovanni dalle Bande Nere, Sir Philip Sydney, Don Juan of Austria, a Knight of Malta or Sir Walter Raleigh?)? I would do my best to encourage you guys to have fun and in the end we will be full of jollity when we watch the blooper reels.
In honesty I like the idea but we all would have to work together to do this, it can start from (I will use this hypothetical example: Me, Sir Ulrich and Sir Matthew would film a segment either in Pennsylvania or New Jersey, once the filming is done, I send the copy of the footage to Sir Edward to compile it with per say him, Sir Brian, Sir Nathan and Sir James. When he gets both footage in, he slaps them together and we have our film) combined teamwork despite long distance. Now if we want to film all of us together, a solution that would come to my mind would be to film nearby a Ren Faire where we are going to be at.
I must profess that this is just my idea, take it or leave it.