Is there going to be another Metal Gear Solid for the PS2

Doubtful as the PS2 is for the most part retired save for some of the more commercial game companies hoping that a port to an outdated system will earn them more money.

Since the PS2 as of January of 2011, there has been:
Metal Gear Solid: Portable Ops (PSP)
Metal Gear Solid: Peace Walker (PSP)
Metal Gear Solid: Rising (PS3, 360, PC)
Metal Gear Solid 4: Guns of the Patriots (PS3)