Are there any self-hosted equivalents to Sendgrid, Mandrill, and other like services? With Mandrill, for instance, there are a number of features like bounce and open tracking, all exposed over a nice user interface. I'm looking for a similar technology, but one we could host in-house (I'm aware about the need to warm up IPs, etc). I found one solution called MessageGears but it looks like they're maybe more geared towards large enterprise implementations.
The problem with such in-house systems is that they either concentrate on the laborious task of sending out emails efficiently (and thus, lack a friendly interface) - or they do the opposite which is they have a very nice interface, but not as robust in the meat and potato department of sending messages out.
Ideally, you would want a combination of something like Sendy + a very fast email relay. I can recommend socketlabs for the second part.
They have two main products - an assembly server (think of it like a very robust templating engine), and a MTA. Combine the two for your own hosted campaign management server. Their MTA server is especially robust and full featured; and they have a comprehensive api as well.
I will warn you though - these products are designed as fast delivery engines, so unless you have a large volume of emails they may not be the best solution. The second thing which I alluded to a bit is their interface; its not the best but it will get the job done; have a look at the screenshots and judge for yourself.
You'll have to build something on top of this yourself. Sendy is a good candidate to customize for this.