I think there are few vehicles produced specifically for this limited role today.  IFVs give infantry significant integral fire support, especially the Soviet-designed BMP with its 73mm gun/launcher.  Modern main battle tanks fire a large HE round, and large forces employ tanks and infantry together.  The Soviet Union, for example, deployed the 2S1 and 2S3 howitzers with forward units, to provide heavy direct-fire support but also work as a general indirect-fire artillery piece: fulfilling the role, but more flexible.  — Z. 2006-09-03 12:42 Z