I'll explain the rationale for each team afterwards, but I'll post the trade first:

RealGM Trade ID #4682114

Warriors trade:
Baron
SJax
Al Harrington

Warriors receive:
Sheed
Odom
Ariza
Mihm

Why for the Warriors: move the bad contracts (and the potential bad contract for Baron), get back expiring players who make a ton of sense in the system.

Lakers trade:
Odom
Ariza
Mihm
Future pick

Lakers receive:
Chauncey
Steven Jackson
Amir Johnson

Why for the Lakers: They get a prototypical PG for the Triangle in Billups, a compelling (and clutch) SF in Jackson who is a killer on a top-level team, and a utility big in Amir.

Detroit trades:
Billups
Sheed
Amir Johnson

Detroit receives:
Baron
Al Harrington
LAL future pick

Why for the Pistons: They get younger and the guard rotation of Baron/Rip/Stuckey would destroy humanity.

Back to the Warriors:
2008/2009 Warriors:
PG: ??? (Shaun Livingston?) / CJ Watson
SG: Monta / CDR (1st rounder) / Marco Polo
SF: Odom / Ariza / CDR
PF: Sheed / Wright / [Filler]
C:  Beans / Sheed / Wright / Hardin (2nd rounder)

2009/2010 Warriors:
PG: ??? / ????
SG: Monta / CDR / Marco
SF: CDR / ????
PF: Wright (Sheed?) /
C:  Beans / Wright / Hardin

That team with the ability to sign or S+T Odom, Ariza, and Sheed, coupled with picks. Oh, and they'd have $30 million in cap room.