This will not help you in your 2-3 day time frame (well, maybe with Prime)... but look up Blue Sea Systems. They make items to what you are referring to and those items are generally made for boats. Boat electrical systems are very similar to what is found on RVs.
I actually installed a 6 fuse version of this for accessories on my ATV and it works as I would expect.
Blue Sea Systems ST Blade Fuse Block - 12 Circuits with Negative Bus & CoverIt does not have a household style bus bar for +, you would need to also install connectors. Good news is, you could independently use different fuses. Or maybe Blue Sea Systems makes something exactly as you are looking for but was not part of my search criteria.
