Well you are just in luck. I work for a company called JumpNode Systems and we recently created a network monitoring product:
www.jumpnode.com Everything is configured before you receive the JumpNode so all you have to do is plug it in on your network via ethernet behind your firewall/gateway. You can configure pretty much any check you can think of for hosts/devices on your network. Alerts can be sent via email, txt, or pager. Cell is in the works or currently in a testing state(can't remember). Also, alerts can be configured for certain time intervals and can be set for individuals, groups, or a hierarchy of individuals. We also added a couple new features recently: Autodiscovery scans the networks for devices and available services to monitor on those devices/hosts, i.e. ssh, http, etc. The interface is accessible through web browser with real time graphs and data. If this sounds like something you'd be interested in, pm me and I'll get you more info.
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