If you honestly want to be "green" you can make changes to your personal behaviour (such as using CFLs, recycled packaging etc.) and not rely on some company to hold your hand and make you feel like you're making a difference for a little extra cash.
I personally tend to lose respect for companies that try to upsell their "green" options, much in the same way I am dubious of extended warranties.
I also hope you realise that even if they were to offer a "green" option it probably wouldn't mean they're going to stick a windmill on top of their colo, they'd just use your extra cash to offset the environmental cost of the electricity you used, much in the same way you can.
Don't get me wrong, I a happy Slichost customer and have made efforts to recycle and use public transport for the environment's sake since I was a child, but this recent rash of "green" buzzwording really ires me as it seems to be used in a most insincere and vapid manner, instead of people actually taking a rational, pragmatic approach to environmental efficiency.