Clay @ Riff Raff can get you the bigger trans pan/diff covers.
BD-Power Deep Sump 4R100/5R110/E4OD Transmission Pan - Riffraff Diesel Performance

If you are looking for someone local to source parts thru, this mob are pretty good: F250 canopy, 2014 f250 canopy, Canopy, F350, F250, F350 canopy, Long range fuel tank, F250 long range fuel tank, F350 long range fuel tank, F150 , F150 canopy, F250 bull bars, F350 bull bars, F series, F series canopy, Service Workshop, F250 workshop

Although, I'd probably look at spending money at upgrading the trans, the sump will help a little, but won't save the trans from going south if/when it wants to.