Re: HDMI to U2711
The article to which you refer is regarding power provided over the cable, which I assume you are stating is an issue over HDMI in the same way as it is over DisplayPort. This is a related but different question.
The O.P. is purely about being able to obtain full (i.e. 2560 x 1440) resolution over an HDMI connection to a U2711.
As mentioned above, this is possible via a custom resolution or by manually editing the EDID file (or preferably if Dell would create and issue something to update the EDID file to include 2560 x 1440 as a selectable option).
To be honest, I'm a bit confused about your post. You mention using a HDMI to DVI cable to run max resolution and then mention a sky box running 1080i.
Firstly, I'd be very surprised to learn that you have a HDMI to Dual Link DVI cable (even if the cable looks like it has a Dual Link DVI connection) as apparently you need active electronics to convert the single link HDMI signal to a Dual Link DVI signal. Otherwise, its is acting as a HDMI to Single Link DVI cable which I understand would not have sufficient bandwidth to carry the full 2560 x 1440 resolution. However, if you're referring to 1920 x 1080 as being the full resolution due to Dell's stated native resolution over HDMI then this would make more sense.
AFAIK, in terms of bandwidth requirement, 1080i is half of 1080p (i.e. Dell's stated native resolution of the U2711) which is in turn half of 1440p (i.e. 2560 x 1440 progressive scan).
As for jd1977's comments on the article, s/he appears to simply be asking for a HDMI to DisplayPort cable recommendation, so I don't understand the relevance (and s/he's connecting to a U2311h not a U2711).
Regardless, I suggest you create a separate thread for your problem; however, I concur that there appears to be unresolved issues with power saving / shut down / display driver crash & reboot etc with DisplayPort and HDMI connections to the U2711.