EDIT 14/03/2019: I have replaced all files with properly sized version for a Huge creature. There is a hollow version for STL/DLP printing as well as a solid version for FDM printing. Use the same base for both versions.
I made a Behir for my own miniature collection for d&d use and I thought I'd share it since I know how hard is to come by.
The sculpt is approximatively 93 x 80 mm wide and 54 mm tall, its made to be a huge creature but, of course, you can rescale it to fit your purpose.