I've had lots of success collabing with other authors. Perhaps you haven't found the right chemistry?
That's entirely possible--it's a matter of time too. Now that I'm not working anymore, I just might try it. I commented somewhere above that I think the writers have to feel fairly strong about their writing to undertake it, perhaps feel evenly matched. Something for me to think about....
I'm looking forward to your fic as well, and I have to say, WHAT THE HELL IS THAT ICON!!!