Front-mounted saddle tanks from Lakestate MFG are designed for AFS connect magnums and John Deere 8 series tractors. While I worked on the STS, the 66 series, and other projects, these tanks served as a "fill in" project to keep me occupied and release something.
Specifications:
450-gallon capacity
$15,000.
contains several kinds of sprayer fills (fertilizer or herbicide, depending on your requirements).
Currently, it is compatible with the following tractors:
US John Deere 8020 Series

Schaben Modding is credited.