This here's a page for ideas on how to drive your marshal nuts. Mostly it's about combinations of edges and hindrances that ought to be illegal, but aren't explicitly forbidden by the rules.
The Quicker Picker Upper
The rules for Scrawny says you can't be a Big-Un if you take Scrawny. They don't say nothing about being Brawny and Scrawny, though!
Size Matters
Want to be Brawny but don't want to spend 3 points on it? Take Big-Un and Fleet-Footed for a total net cost of 1 Point.
Courage Under Fear
Here's a trick for the faint of heart. Squeemish? No problem! Take Brave to cancel out those Guts check penalties, and you've still got 1 point of Squeemish left over to spend on something else.
Deep Pockets
The rich get richer and the poor get... a little dinero! Tired of having to walk everywhere 'cuz you can't afford a horse? If you've taken the Poverty Hindrance, pick up 1 point of Dinero. Now you've got $300 and an extra $100 stashed away somewhere. Total gain: $150 and 2 points of hindrances.
Extra Thick Skin
Harrowed characters get to ignore up to two wound levels of penalties. With the Thick Skin Edge, they can ignore up to three! This is official, too... Shane said so.
I don't quite remember where I found this, nor do I know the name of the original author. I didn't compile these, but I like them (well as a player, anyway. Maybe not so much as a Marshall)