A programmer from Berlin has created a website by the name of Dildo Generator which allows you to design your very own dildo using 2D design tools and generates a 3D representation next to your 2D design.
Once complete you can download an inverse mold of your creation as a .STL file and use it with compatible 3D printers or send the file to a company who do 3D printing for you and have your mold created which you can then fill with silicone to create your own sex toys and as you have the mold you can create as many of your design as you wish in varying colours!