The mgs pack should be here very soon. The games 1.06 update was in preperation for the pack. After installing the update and then comparing your lbp trophies to a friends you'll notice 11 additional trophies that involve mgs and paintball(?). It appears likely that the pack contains 5 levels.
QuickFire Artiste
Fire 40 paintballs in under 5 seconds
Rexecutioner
Destroy the Metal Gear REX boss
Ace Act 3 and Act 4
Ace Act 3: The Mission and Act 4: The Level Factory
Ace Act 5: The Boss
Ace Act 5: The Boss
Paint Splurge
Fire 5,000 paintballs
Virtual Survivor
Achieve a score of 3,750 in the VR Survival Challenge
Diamond Hunter
Destroy the 5 hidden target diamonds in Act 4: The Level Factory
Speedy Rexecutioner
Destroy the Metal Gear REX boss in under 2 mins 30 seconds
Thrifty Painter
Complete Act 3: The Mission firing less than 125 paintballs
METAL GEAR SOLID® Booty Master
Collect all of the METAL GEAR SOLID® prize bubbles
Paint Sharer
Publish a level containing the METAL GEAR SOLID® Paintinator Powerup
