some talented members that may be able to help you out, but it's not going to be particulary inexpensive as it's terribly time consuming and that only gets more so if it's a "one off" - a tank shape they've not made before. While it's well worth what they charge, if it's out of your comfortable price range you can reduce the cost with some of your own labor.
While it does take a bit of time, it's not particularly difficult to cut, form & fit your own tank panels & fittings, then bring it to your local welder to be TIG welded or even brazed. So long as all your seams are flush and they've skill - it's a pretty quick and easy task for them, and that means savings for you heh
Here's a basic intro;