Maybe you should considder using HAProxy (http://www.haproxy.org/)? I have used it a little bit, it seems quite easy to get started. Without having tested in depth I think that could do the trick. This article might be to some inspiration:
How to Build an High Availability MQTT Cluster for the Internet of Things | by Lelylan Blog | Medium
I haven’t really spent much time looking into it, I have a lot of other projects that I need to deal with first. But it looks interesting…
Thanks, will have a look at that 
If you find something interesting I would be happy if you will share your findings…
I got stuck indeed, specifically due to the fact that OH2 the channels need a specific type.
The binding is/was working, but not in a very intuitive way. I’ll take another stab at it over xmas holiday
FTR: I think MQTT should be done in a pretty similar way as it has been discussed for KNX, i.e. with “generic” Things on which the user can define any number of channels, referring to a fixed set of channel types (more or less one per item type). There shouldn’t be anything blocking an MQTT 2.0 binding 