Has anyone been able to integrate those EnOcean-powered “Friends of Hue”-switches? There are a couple nice one on the market now that would fit nicely with my existing switches around the house.
There have been a few attempts, but I haven’t heard of anyone who has it working yet.
One of the tricky things is that you cannot change the Zigbee channel on the smartthings hub except by completely resetting the whole thing, and even then, you don’t get to pick what the next channel will be, you just get to try again for a random selection. And only some of those channels will work with the friends of hue devices.
In addition, different manufacturers have assigned different channels to their switches.
So first you have to find out what zigbee channel the switch uses.
Then you have to go into the IDE and see what Zigbee channel your hub uses. And it has to be one of the newer hubs, preferably the V3/2018 model.
If the channels match, you can give it a try, and it may work as an on/off switch. It’s not likely that you’ll get a dimmer function, but maybe.
If the channels don’t match, you have to check and see if the switch has a way of changing its channel to the one that your hub is using. But these switches typically only offer a selection of three or four channels and the hub can be sent to quite a few more than that, so there’s no guarantee that it’s even possible.
If they are on the same channel then you might be able to create a custom DTH for it, but I haven’t heard of anyone who’s gotten that far. 
There’s an existing discussion thread for these devices, but as I mentioned, no one has yet reported actually having them working with smartthings. They do work well with the hue bridge, though.