Yeah, what happened was that MacFarlane bought the rights and wouldn't let anyone publish them, even though somehow they were tied to Gaiman (he wrote the run following Alan Moore's run, which was never finished). Gaiman won the lawsuit against MacFarlane for not giving him rights on certain Spawn characters, and part of the litigation allowed MacFarlane to continue use of Gaiman's characters if he handed over the Miracleman rights. Now, I believe, Gaiman is trying to finish up his run so he can have Marvel republish the series in its finished glory.
I befriended the LCS manager a few years back, who had spent hundreds of dollars tracking down each issue and let me borrow 'em. I tell you, what Moore did there is so different from Watchmen. In Watchmen, he turned the superhero concept upside down. In Miracleman, he creates, quite possibly, the definitive superhero concept. And what makes it work is the villain is so evil, so awesome, that you have no choice but to be captivated, even when Moore turns up the destruction and collateral damage all the way up to 11.
And it's so cinematic, and easily the most simple of Moore's works to adapt to screen, that the first person to faithfully adapt Moore's run will give us all the best superhero film put on celluoid.
