Sometimes one desires to know whether an optional module is available. A command like `eselect list-modules $module` that returned 0 or 1 would be helpful. Currently, the only way I see is trying `eselect $module` and checking whether it spams you with error messages or with help messages. Trying `eselect $module` also gives a return code, but it would be more convenient to have a way that you didn't need to do >& /dev/null with.
Pioto, Ciaran and me discussed a new 'modules' module with 'list' as default action and an additional 'has' action. Targetted for 1.2.0. We can start working on that once I've branched out 1.0.x.
This is in SVN trunk since a long time.
Fixed in eselect-1.1_rc1.