Located on Mount Mobius, the Veg-o-Fortress was Doctor Robotnik's primary Badnik processing plant for some time during his rule over Mobius. In the first part of The Sonic Terminator arc, Trusk had captured all of the Emerald Hill folk and was to take them to the Veg-o-Fortress. His ship never made it there since it was commandeered by the Freedom Fighters with aid from Captain Plunder's crew.
The Veg-o-Fortress is based off the location of the same name in the Sonic Spinball video game. Although it never actually appeared in Sonic the Comic, if it was anything like its game counterpart, it would have been defended by a convoluted pinball-style security system. Unfortunately, we shall never know for certain.