I thought the headphone jack was in an awkward place too but then I realized that they put it there so it won't get in the way of your hands when holding it.
It probably will not happen. People haven't got a flashcart to work in DSI mode so it is highly unlikely they will be able to have a flashcart running in 3DS mode or even hack firmware.
If you are looking for an affordable gaming laptop, Asus has some that are a great bang for your buck. Most are over your $700 price point but most are also under $1000. I bought my Asus G50V last year from Best Buy for $900 and it is amazing. I just completed Mass Effect 2 last week and it ran...