this concept is quite....shall i say, badass. your concept art looks like it was drawn up by someone working for GL himself. you should be very proud. i have always wanted to see someone do a fem'mando the right way (most of the fem's out there just look like a skinny fett, like *jango at age 12; ...and here he is before his first date*...lol).
but where does your custom fit into the "arsenal"(if there is such a thing) of mando troops? she looks kind of like a scout/sniper/assassin type. i started on your back story you wrote, too. i must say you seem multi-talented. you should just go ahead and write yourself up a novel and run everything by GL for a part in the next SW flick.