Unless they made major changes to the code from the Consumer Preview to now, you can still use them.
I know this says Developer Preview, but my Consumer Preview desktop looked almost exactly the same. I was able to have Metro going on my main monitor on the left and my gadgets on the right. I even played Cut the Rope via Metro while having my gadgets on, Tweet Deck and Destroy Twitter going.
The only difference between the gadgets now and from when they were first introduced with Vista is that they dont have to be on the "sidebar" anymore. They can be anywhere on the desktop now. I remember Vista had to have the sidebar loaded in order for them to work. In fact I think the process these gadgets all run under is still sidebar.exe if I am not mistaken.