we're talking about the same arrangement i tend to think in row major for arrays as habit (rows, columns)
best so far i've found is this:
which can be found on amazon for about $215 USD and seems to have the adjustment and weight requirements to hold 6 x 22" widescreens in a comfortable viewing position.
i'd rather have a stand instead of the the desk mount due to having glass topped desks, but i could rig something safe up with this using support blocks on either side of the glass to spread the strain.
i'll look more closely after i see the results for 3 or 4 screens.