Kmrtnsn
Explorer
This post is spot on. I concur with Billiebob regarding width matching your track as well as mirror visibility. The traditional military quarter tons are scaled to flat fenders which are laughably tiny compared to modern Jeeps. They disappear completely behind a pickup truck. While setting the standard for the adventure trailer format, I honestly find them to be a bit tight on space and think a little bigger is better.
Based on what you are describing I would consider 5x8 with an adjustable length/removable tongue. Most of us with 4x6ish trailers have stuff clabbered onto the tongue and sides so you're basically at that dimension anyway. Just make it 5x8 and put everything inside instead. Plus if you ever need to use it for general utility hauling it's way more convenient.
The reason the original M-100 was “scaled” to match the dimensions of the first Jeeps was because is
it had to meet the same loading requirement of being able to pass through the cargo doors of a C-47.