Hi! Is there an interest for this around? 
Let me share our app created for the exact purpose of visualizing your SmartThings devices on your own house floor plan. There is no need to work around in your flat panel, or try to learn a 3rd drawing tool. We tried to create this app with all built-in tools included.
We just released it to production stage (after 6 months of beta testing with folks in this community and on SmartThings user group on Facebook, too). It’s now starting to be used daily by people to view and control their devices. If you need more information, please check out some info below:
Official thread: SmartThings on Floor Plan: View and Control from your House’s Layout UI
Website: www.thingstwin.com
Android: https://play.google.com/store/apps/details?id=com.ThingsTwin.Home
iOS (Beta): Sorry the link may change in the future, as we are under beta for iOS, please visit us to opt-in.