This would go great with the Warehousing mod! Lots of storage space if you're willing to put forth the materials and ground space, lots of options for whatever size you need to work with.
Could you expand it to alter player and vehicle inventory space as well? I think the player inventory is a bit too large--makes circumventing logistical bottlenecks too easy. Train storage is probably where it should be, but the trains should be more expensive!