Right now I have no desire to grind Romulan and Omega marks because I have an abundance of them for little effort and I have a distinct shortage of fleet marks.
I think we should be able to trade Omega Marks for Romulan Marks and Fleet marks, and vice versa. I can grind Romulan and Omega marks much more often than Fleet marks. I think it would be awesome to be able to trade them. I don't mind if it's not at a 1:1 ratio either.
My suggestion is that Romulan and Omega marks be tradeable at a 1:1 ratio and either of the two can be traded for fleet marks at a 2:1 ratio.