"See The Storm," a mini-sermon by Mattie Montgomery, is very impressive. Perhaps not contextually correct in its entirety, but it's still a very interesting idea. And we are to be the hands and feet of Christ; this is a variation of that idea.
To think that we, witnesses of God, are the "cloud" of God's glory is a pretty interesting idea.
I'd like to add something to this as well.
A congregation of witnesses, "so great a cloud" of them, would be a very impressive example. If we let go of our past, give up the dead man of the world and take on the living Spirit of God within us, if we no longer live as ourselves but live as Christ living through us, we can embrace the lessons learned from living as the world--we must embrace our testimony, the testimony that God has given us by His grace and for His glory.
If we hold to this this, if we let Christ live through us, if we take our testimony into the world as an example of God's glory to show others what He can do, there is no force on earth more powerful; mobile, pointed Christians who love and want so desperately to see others come under the grace of God have no match in this world, nor do the powers of darkness have a foothold in their presence because Christ is living through them.
And the congregation of these witnesses, a gathering of these examples of His glory; anyone coming into this would be stepping into a great cloud.