maybe Overkill, and no MS-Win support (but it might work with cygwin type environment) is PBS. it's widely used in I2/Globus/Grid projects. you would still need to do your template part, but PBS can schedule/manage the jobs across available nodes. i don't use it myself, but we have a (ew, 600ish nodes, 2-4 CPUs/node) cluster that's booked for the next year or so managed by the PBS stuff.

IRIX and Linux are on the supported list (with other *NIX flavors as well).