For monitoring and graphing of servers and services, I would like to make a setup where collectd is the agent, collecting the data on the server, and munin is on the monitoring server, collecting the data from the agents an process it.
Reasons for this setup, is that collectd had a smaller footprint on the servers and munin (v2) has a better frontend.
I was wondering if there's an interface for this connection, or if someone has an opinion about why I shouldn't do this.
You could have all your collectd-nodes push (with the network plugin) to a central node, which in turn write all the data to rrd-files. You can now "fake" munin into using those values for graphing. So, both tools do not know about each other and are just using the same files.
However, I recommend to use the Collectd Graph Panel as RRD-Presenter. It's simple but configurable. It is a simple PHP script so deployment is super easy.
I doubt this can be accomplished. Collectd uses a push paradigm while Munin uses a pull one, so you should at least find a way to make the data available to the Munin frontend. Collectd has a quite wide range of web frontends available, are you sure none of them suits your needs as much as Munin does?