Today, we have a pair of vault releases from two acts with rich catalogues coming your way over the Internet.

If you're a hard rock fan, the news of Metallica's recent 30th anniversary concerts, where they  played hours of hits and rarities over four star-studded shows at San Francisco's Fillmore West, have probably got you really excited. (They have us excited at Second Disc HQ, too, thanks to a perfectly logical assumption that any celebration of a band this beloved is bound to lead to some reissue/compilation/box set activity of some sort.) For now, though, we do have some bonuses to report from Metallica's vaults: Beyond Magnetic, a four-track digital EP consisting of rough mixes of tracks recorded during the sessions for the band's most recent album, 2008's Death Magnetic. The four tracks - "Hate Train," "Just a Bullet Away," "Hell and Back" and "Rebel of Babylon" - were all played at Metallica's commemorative shows and subsequently gifted to members of the band's fan club.

"They are ROUGH mixes, unfinished to their original degree of mixing from March '08," the band said in a statement. "These four songs were released as gift to our closest fans, the members of our Fan Club, to enjoy. Now they're being made available to you." The EP will be available exclusively to iTunes for one week, after which all digital retailers will carry it.

Elsewhere, Duran Duran - currently on tour in Europe - have a most interesting treat for their more dance-oriented fans: in November, Capitol/EMI released four sets of remixes of classic hit "Girls on Film," all commissioned in 1998 to promote the Greatest compilation and commercially unavailable since. Club and trance producers Attica Blues, Tall Paul, Salt Tank and Tin Tin Out each contributed their talents to the mixes, making for a fresh spin on an old favorite. Each set is available through all digital retailers, but Amazon U.S. has each two-to-four-track set for 99 cents each, a considerable bargain.

After the jump, enjoy purchase links and track breakdowns for all of these digital sets!

Metallica, Beyond Magnetic (Warner Bros. (no cat. # - digital), 2011)

1. Hate Train
2. Just a Bullet Away
3. Hell and Back
4. Rebel of Babylon

All tracks recorded in 2008 during sessions for Death Magnetic (Warner Bros., 2008) and are previously unreleased rough mixes.

Duran Duran, Girls on Film: Tin Tin Out Mixes (Capitol (no cat. # - digital), 2011)

1. Girls on Film (Tin Tin Out Mix)
2. Girls on Film (Tin Tin Out Instrumental Mix)
3. Girls on Film (Tin Tin Out Radio Mix)

Duran Duran, Girls on Film: Salt Tank Mixes (Capitol (no cat. # - digital), 2011)

1. Girls on Film (Salt Tank Mix)
2. Girls on Film (Salt Tank Mix Instrumental)
3. Girls on Film (Salt Tank Mix Radio Edit)

Duran Duran, Girls on Film: Tall Paul Mixes (Capitol (no cat. # - digital), 2011)

1. Girls on Film (Tall Paul Mix)
2. Girls on Film (Tall Paul Instrumental)

Duran Duran, Girls on Film: Attica Blues Mixes (Capitol (no cat. # - digital), 2011)

1. Girls on Film (16 Millimetre Mix)
2. Girls on Film (16 Millimetre Instrumental Mix)
3. Girls on Film (8 Millimetre Mix)
4. Girls on Film (8 Millimetre Instrumental Mix)

Tin Tin Out remixes (1-2) originally released on EMI 12" promo 12 GOF 2, 1998. Track 3 previously commercially unavailable.
Salt Tank remixes (1-2) originally released on EMI 12" promo 12 GOF 2, 1998.  Track 3 previously commercially unavailable.
Tall Paul remixes originally released as EMI 12" promo 12 GOF 1, 1998
Attica Blues remixes originally released as EMI 12" promo 12 GOF 3, 1998