Rogue build help

[Eonir]

So basically, I need to create a level 9 gestalt character. I came up with a really awesome (kinda) idea. He was a rogue8/marshal1//spellthief9. He had really awesome SA, his charisma of 20 worked wondrously with his marshal dex aura (the party is a lot of sneaky guys), and spellthief gave just the perfect amount of casting I wanted for him (he was a nobles son who wanted to be a wizard, but when the war broke out he joined the army and became a rogue, but kept his magic studies).

I thought he was perfect, until I found out that SA from rogue and spellthief in this case didn't stack.

So, I need a build. Pretty much nothing is taboo. 32 pt buy. Human race (non-negotiable). And if at all possible I would like him to stay LG.