I have been using this putty recently and I am quite happy about it.http://www.sentosphere.fr/accueil-loisirscrea.html
I don't know if it can be an alternative to Sugru because I have never tried Sugru but anyway it has been quite useful for me. It's very, very light. It's a bit wet when you take it from the box and dries in one or two days, or even faster depending of the thickness. I am using it to create standoffs that I can easily glue on fabric. It keeps some elasticity after drying. It seems to be nonconductive.
It's sold in toy shops, in craft hobbies shops (such as Schleiper here in Belgium) or online, probaly mainly around France because it's branded by a french company (but made in South Korea). It is available in many colors. You can buy it color by color (around 4 € / 30 g) or as boxes of several colors.