By accident just discovered something last night. I have two 2TB Hitachi externals. On is the newer XL model and the other is the older one made for Hitachi by SimpleTech. The SimpleTech version is not green (the XL version is), but also comes with a software USB accelerator (claiming 25% performance increase which it does do). The XL version does not include the acelerator software. The discovery is:
IF YOU USE THE ACCELERATOR SOFTWARE WITH THE XL VERSION, THEN THE XL ENCLOSURE NO LONGER TIMES OUT (ie, drive remains full up active)!
So looks like that's part of my fix. Mainly, that there are for me many work streams in which a mandatory 9 minute timeout is inappropriate (ie, nuisance). Effectively, green drives need a mechanism to override the green feature (and better yet, would be to allow user setting of the timeout).
Note: In the case of the WD's, it seems that this capability is built in, but I was totally unaware of this when I purchased them (admittedly long ago).