What if you run a report using an automation policy? The query is included in the KB below and would give you an idea of the health of your package servers. Basically it looks for what isn't in a Ready status, and a package server could have been removed recently and therefore the NS still sees those Ready statuses.
http://www.symantec.com/business/support/index?page=content&id=HOWTO1108
But I think this gets you pretty close to what you need. Really you would want to use monitor solution and do an ICMP Monitor Pack with your Package Servers as the target. Using monitor solution would let you look at things like disk space as well.
Does this help?