Green research focused on HP and Sun,

Sun
Not very forth comming, if phoned they will direct you to the VAR, is messaged they will direct you to a random weirdo in a call center who will redirect you to the VAR! Sun Has a really good “reuse” policy for data center components, servers and other equipment.

Most importantly they are measuring power consumption to transactions which is the most important metric for efficiency to carbon emission.

Here is their public corporate carbon statement > http://www.sun.com/aboutsun/csr/report2007/eco/carbon_reporting.jsp

Here is the bench mark for the SPARC t2000 > http://www.sun.com/servers/coolthreads/t2000/benchmarks.jsp#21

HP
Very forth coming, great site with lots of information (but not transactions), and a nice flash animation of a tree. Most importantly they not only provide power consumption usage they also provide toxicological information and reuse help
http://www.hp.com/hpinfo/globalcitizenship/environment/
http://www.hp.com/hpinfo/globalcitizenship/environment/productdata/edsenterprise.html

Importantly, I could not find the per product manufacturing toxological or carbon cost from either sun or hp.
However both companies have a real focus on addressing the ewaste issue.