A few days ago I ordered two silicone heated bed custom made to my printers from a chinesse company called
Keenovo. They had shipped today and it will be 15 days to arrive to Spain.
It cost 102.50$ each, but are 415 x 260 mm, 5mm thick silicone rubber insulation, 220v AC- 600W, and custom holes to attach fixations and thermistor.
They sent me a photo of the finished product before it been shipped and looks like very good: