what about just using two hdp2 units. They can be had for $800 new on ebay.
Scenario 4
$800 | hdp2 (new off ebay)
$800 | hdp2 (new off ebay)
$1,100 | V3 (used)
$1,100 | V3 (used)
=================================
$3,800
That gets you 4 channels of V3 pre/ad, 24/192 capabilites, word clock syncability. all for less than either scenario involving a 7xx box.