I have recently been working on a project trying to integrate a 3d model (dollshouse) into my virtual tour.
I created the dolls house .obj and hosted it on Sketchfab.com. Umalo developed a plugin (hopefully available at some stage to buy) to enable you to click on an annotation within the sketchfab model and link it the panos in your tour.
3d Models can be created with free software sweet home 3d and uploaded to sketchfab.
Here is the result