Absolutely Lynn,
Maybe one of the smaller sunsparklers, or sedum 'Pork 'n beans'? I have this big, gorgeous delosperma NoID that sits up a good 2.5" + a little more when it's gets some well established mounding going on, that'd look nice in there too. Of course I'm sure you won't have any trouble coming up with something with a garden collection like yours.
I have seen some photos of Julia's work online, it's pretty impressive stuff.
-Sol
