What Bullitt set up would you recommend with a custom box to carry 3-4 kids once a week 1-2 kids everyday. Big big kids 150cm tall.

Just sold my Load 75 because I need the width of a custom box. My kids are getting bigger and don’t fit side by side anymore in Load 75 so am considering all the Bullitt options - Bafang, EP801, x or original etc. Will be carrying 2-4 children for short weekly trips, mostly 1-2 children. All kids now 133-150cm now so they are getting heavy. Will definitely be a custom box. Not sure on the specs. Thinking maybe a Rohloff as I was always jealous of others when I had the enviolo on the Load 75.