There may be another way to do it, but I'll need confirmation from you experts since I just opened my Nstinct for the first time last night. I think I have all the necessary equipment, except a sub-$25 IR543.
In my home theatres' arsenals are a couple of Harmony remotes and two Nstinct remotes. I want to either use the Nstinct remote for everything, or the Harmony remotes for everything. An option might therefore be to purchase an IR543 or two, program a Harmony with X10 IR codes and then learn the IR codes on the Nstinct. This will allow me to devise X10 command-containing macros along with regular IR components. I could still also use the Nstinct remotes RF X10 commands for out-of-room X10 events.
Alternatively, if I program one of my Nstinct remotes with X10 IR codes, I could then use it to learn these on the other remote, and vice versa.
I wish that there would be a firmware update allowing us to have this "mixed-macro" flexibility.