The email issued mentioned earlier this week is now fixed! You may also have received previous emails that were meant to be sent over the last few days - apologies, this was a one time issue and shouldn't happen again!
In 2015 there were not a lot of options so I put a Streamlight TLR-1S, 69210, on mine with their magazine tube mount, 69901. Haven't looked at what is out there because I have been pleased with this setup. The light is quite bright and is a nice balance between flood and beam. Of course that is subjective. NOTE: If you use this mount you have to order two (2) and cut the Picatinny Rail section off of one of the mounts and fasten it to the mount you will use. Stack them. This allows clearance for Mossberg's sling mount and also the Magpul forend in my case. Zoom in on the mount in the third picture and you will see the rail sections stacked. Like I said there is probably something else out there now but I haven't looked.