I started doing box-art/display kits for Round2 through a friend-of-a-friend and a dusty old model.
Way back when the AMT Po Shop '64 Ford was released my local LHS proprietor asked me to build one for him for display in his store. Fast forward a few years....a friend of his (John Greczula from Round2) was visiting his house and spotted the old Galaxie sitting in a display cabinet. At the time ihobby 2008 was coming up and John needed someone to assemble a couple of test shots for the show. I was offered the task, I figured "this might be fun", and that led to 60/70-something kits since then.
Yes it's fun, but there are some challenges. Time is a big factor (usually 7-10 days in my spare time), and sometimes you're working with test shots that aren't quite production-ready. The highlight for me was the snap '66 Batmobile....I had to mate a resin prototype body with an early test shot....and it had to be painted AND pinstriped (somehow). I got it done, though.
I have to give credit to the other guys who have done work for Round2....I've done a bunch of stuff for them but I'm not the only one, and their work is amazing.
As to "where are they now?"....the kits usually end up in the Auto World store in Indiana if they survive the beating from being shipped to shows etc (I know of at least one that was basically trashed).