Another good manufacturer Stanley (Harrisburg, Pa.) AFIAK they don't make make custom but Like Eaton/Detroit they have detailed info on many of the specific springs, many cross referenced to the original part numbers.

If you can't buy locally (call Stanley in Harrisburg for local retailers) Stengel Bros is a retailer that will ship to you. They have both a .net and .com website - don't know why.

Here's a direct link to Dodge leaf packs
http://www.stengelbros.net/Dodge-Passenger-Car-Leaf-Springs_c_194.html