@devlin_gandy you (currently) cannot switch textures on a static model without using the API. However, as mentioned by @bartv and @shaderbytes we've just released a simple feature to create simple animations from static models.
In your case, you'd have to generate one for each texture, zip all those models and add a file named
Let's say you have mural1.obj/mtl/jpg, mural2.obj/mtl/jpg, mural3.obj/mtl/jpg, all you'd have to do is to put
(the first column is a time in second and the second a model to display for that time)
sketchfab.timeframe file and it would create an animation, displaying one model after the other every 10 seconds.
Right now you cannot simply add a texture for a model so you really have to duplicate the geometry too (making the final output more heavy than necessary) but that's something we could improve.
Would you give that a try @devlin_gandy ?