NO!
U2 take forever to make albums for a reason - they carefully select what songs are for public consumption and what songs are not. The theft and subsequent release of the Achtung Baby Outtakes proved that U2's unfinished material is indeed not for public consumption but merely something with interesting musical fragments.
These songs are unreleased and outtakes for a reason. With a band like U2, who have been around 25 years or so, they should have had at least one official CD of outtakes or unreleased material but they don't because they are no sellouts and aren't that opportunistic with cashing in on fans like Springsteen is.
Springsteen is the ultimate in opportunism. When his career turns sour, he does mellow movie soundtracks. When that one lost its charm, he had a "desperate" reunion with his E-Street Band, and finally he cashed in on grieving America by making a 9/11 album. Springsteen is just a parody of his old self. Meanwhile, U2 are still in fine form, never desperate for cashing in like Springsteen does.
Releasing outtakes and unreleased songs is like a car manufacturer selling the junk metal scraps when the chasis was chiseled to shape. U2 writes songs, the good ones they put in the album. The not-so-good-but-good-enough ones they release as b-sides. They rest are scrap metal. I am sure everyone here will unanimously agree that taken as a whole, the album tracks are better than the b-sides. So why release something that is even more substandard than a b-side? Only desperate Springsteen would do that.
I have too must respect and love for U2 to even think they'll release something that desperate. For the love of U2, let's all hope they don't do a Springsteen. But then again, U2 members have twice the IQ of Springsteen anyway.
Cheers,
J