ADSLGuide has caught sight of further information from BT regarding their forthcoming 2Mbps to 8Mbps broadband ADSL trials. The services will be fully rate-adaptive (no specific limits, except your line quality):

Service - Downstream Speeds - Upstream Speeds

BT IPStream Home Max - 2272kbps to 8128kbps - 64kbps to 448kbps
BT IPStream Office Max - 2272kbps to 8128kbps - 64kbps to 832kbps
BT DataStream Office Max - 448 2272kbps to 8128kbps - 64kbps to 448kbps
BT DataStream Office Max - 832 2272kbps to 8128kbps - 64kbps to 832kbps

Typically BT is viewing the trial as more of a data gathering exercise and the end product will be subject to change, if there is an end product. Only those already able to receive 2Mbps will be eligible.

BT has warned ISP’s to caution customers on the potential quality, or lack thereof, at peak times. Unlike earlier trials for up to 2Mbps, getting to 8Mbps is going to be much harder and will be prone to greater instability (speed wise) the higher it goes.