That last link worked well to give me more control over what was shown in the sidebar, but I still can't get rid of the homegroup icon on the desktop.
I've tried the oft-circulated tip to disable both homegroup services in the services.msc, but MS seems to have disabled the connection between the services and the icon, so desperate are they for us to use the new feature whether we want it or not. It can't be removed from the Desktop icons settings either, we can disable everything else on the desktop, including far more useful icons.
The libraries and the homegroup are just stuck there, permanently, on this RTM system with whatever updates have been pushed to date. Uck... this seems like such a return to typical microsofty behavior of forcing unwanted features, after all the gains in offering fine-grained control of what features I do and don't use.
Sorry for the rant, I'm hoping a bump might get some new information, and maybe that someone who has control of this might fix it in an update.