The digital work is by Passion Pictures, it lacks something but has some nice elements. The games produce more CG than promo pieces like this though, all the public works and grand architecture create a wealth of renderings and visualisations for us. Here are a few images of stadia and public spaces from various sources that show off some serious visualisation skills and in so doing some cool architecture. iedm even made this proposal for using the site after the games for F1, just to show off that they could.
[London Olympic architecure CG]
Here is a cg fly-through, well fly-over of the Olympic park as well.
To finish up, we like the Australian Foxtel tvc for the games which nicely transforms one athlete into the next. Super super stuff.