Couple things to add:
1.) I don't know why people are using U2's previous timeframes to figure out when this new one will be out. I'm pretty sure none of the boys are sitting at home thinking "We have to rush this one out to beat the 4 year mark!" It'll be done when it's done.
2.) And when it's done, you're looking at single in September and album in October or November. McGuinness is right, it makes no sense for such a monumental act to go anywhere else but the 4th quarter, business-wise. Also, by releasing the single in September, they're eligible for 2 years worth of Grammys on one album, similar to ATYCLB and HTDAAB.
3.) And I don't know if Rubin will pan out or will work for this reason: U2 NEEDS a producer. This band is maybe too creative. I remember a Rolling Stone article around the time that ATYCLB was in preproduction and it tracked the evolution of "Stuck in a Moment" through the course of a day and the song changed drastically. Not only that, but the fact remains that there's often some tension between the direction of songs. And how many times have Eno and Lanois been credited with providing the key element to a song? Well guess what? That ain't gonna happen with Rubin. He checks in every few weeks, listens to what you have, says "good" or "bad", and leaves. He wants songs completed before he records. But with U2, the songs often aren't complete until someone steps in and tells them "hey, don't mess with that one anymore. It's done, boys." I don't see Rubin doing that.
And as for my prediction, I'm saying album is out in November of 2008. The boys aren't working yet, and when they do start, probably sometime in the summer, you're looking at a good year of writing. Luckily, if they ARE going with Rubin, he likes to record fast, which should set us up for a September single and a November 2008 album.
Also, here's what Rubin had to say about the band in an interview conducted after this year's Grammies:
U2: "We've talked about doing some more, but they're on tour," said Rubin, who produced two tracks for the band's recent hits compilation, U218 Singles, including the Green Day collaboration "The Saints Are Coming." "Hopefully we'll get to do some more together."
They're on tour? My guess is there hasn't been much contact between the U2 and Rubin camps as he's a bit out of the loop. And "some more together" leads me to believe that Rubin would be a great selection should the band decide to use multiple producers a la HTDAAB. But judging from Larry's comments in U2 By U2 about that idea, it's unlikely.
Anyway, doesn't matter to me. I doubted U2 after Electrical Storm and they shut me up. I'm sure they'll do it again.
And as for Rubin, God I can't wait for new Metallica and Chili Peppers.