There appears enough room for a drop in dump bed. Like found on some side X sides and the cheap Chinese golf cart style pickups. The space already exists under the bed for the mechanism. Future idea.
1.) Will the battery be actively heated/cooled?
2.) It is my understanding that the Slate uses pouch style cells packed in modules; 2 modules for the ~150 mile, 3 modules for the ~240 mile version. Will it be possible to "upgrade" to the longer range version if needs change?
Or a marked "drill here" or better yet a punch out to access the 12 V battery and perhaps mounting for a fuse block. This would be more in keeping with the DIY mindset.