i'm a vegas veteran, 50+ dvds/1000s hrs, a seemingly simple video wall was a real tough one to do
V12 simply wouldn't render all 6 clips on the timeline together, tho i have a high-end win7 pc...normally vegas ingests dozens of diverse clips w/no problem...
www.tradingjazz.com
UPDATE 31May2015 v5:

this time though it didnt...when trying to render all 6 it would hang 17% of the way through; tried many times... so the fix, ah-hah! I:
a) rendered top row of 3 ladies into an 8gig avi
b) ditto for 2nd row
c) combined both avis to make composite video wall
V12 simply wouldn't render all 6 clips on the timeline together, tho i have a high-end win7 pc...normally vegas ingests dozens of diverse clips w/no problem...
www.tradingjazz.com
UPDATE 31May2015 v5:

this time though it didnt...when trying to render all 6 it would hang 17% of the way through; tried many times... so the fix, ah-hah! I:
a) rendered top row of 3 ladies into an 8gig avi
b) ditto for 2nd row
c) combined both avis to make composite video wall