I'm not aware of anyone offering it as a service, and I don't know how well it would work. Since it's all UDP, there's risk of data loss. We experience essentially no loss within our network (less than one one-hundredth of a percent in testing), but not sure what things would look like going elsewhere.
I know what you mean about fearing the maintenance -- in particular, getting the node.js statsd daemon, Graphite, and Whisper (the default storage and front-ends, in Python) running can be pretty tricky and intimidating. I'd suggest taking a look at the alternate implementations out there -- etsy has a list at https://github.com/etsy/statsd/wiki, and there are a few more not on there as well -- and see if any of them seem more your speed. For us, we really didn't want to introduce a whole extra set of infrastructure requirements to run a Django app and accouterments, which is how we landed on using our own implementation (in Ruby).
