Dynamo Lights

Specialized toupe, not carbon rails.

Cool, so you can use something like the B&M rail mount if you like which will mount it there.

Will a Son one play nicely with the Ixos?

Yes, in fact all the internal electronics and lens are made by B&M. SOn just machine the alu case.

There are two son options. A rack mount and a seatpost mount. The rack mount could bolt onto the bracket that attaches to the rails, and hang just under your saddle. However in this case a saddle back could interfere. For a lot less money the B&M Top Line Small is the same light with a plastic case that'll do the same job.

For the nice SON seatpost mount one it simply has a band which straps to your seatpost.