I'm looking for a person or place in Nor Cal where I can have a custom tank built for my aquatic turtles?

I have two aquatic turtles that I have had for four years. I don't want to have to give them away but I may if I can't find a bigger tank. I have them in a 75 gall tank which is 48"x18". I would like to have a tank that is wider. I thought of purchasing a 125 gallon tank, but it is the same width. If there is anyone that knows a person or a place that does custom tanks I would appreciate it if you would let me know. Thank you!