I've now just added some of the No Days Mosaic Mesh to the shop. This is a mesh that you place the tesserae on then heat the area up using a heat gun and this activates the glue in the mesh. Once dry you have a very strong bond to your tesserae but if you want to change anything around then you can just heat it up again and move the pieces around. There is a video on the page showing how to use the mes. Click here
I've used this mesh and it does get around the problem of what to stick your tesserae to the mesh with and the adhesive doesn't spread all across the back meaning there is enough of the backs of the tile free for the cement to grab onto.