What are your other requirements?
- Is this for a production or a one of a kind hobby/repair project?
- How budget aware are you?
- you mention portability. How often would you need to unplug it? And will it be done by you or someone who requires a bit more user proofing?
Have you considered using more than one pin per pole? Ie if you had a 15pin connector, that can take 3A per pin, then shorting 3pins will give you 5 pins 9A. There will be more considerations to this though. Like how can you make sure that the parallel pins present a similar resistance, so you don’t get an unbalanced load.
I use something like this when repairing screw terminals that my students have applied too much torque to and broken the through hole pins on. It’s a great type of connector. But if we’re talking portability, then it’s maybe not the most ergonomic.