Trust me... a Gunvault is your solution....
While I agree that the most important safety is between peoples ears and that software is more important than hardware. The reality is that young children make mistakes, and a mistake with a loaded firearm is too much to risk. So no "up high", "night stand" or "hidden" guns in my house.
and here's a link for a great price on one.
http://www.amazon.com/Mini-GunVault-Optional-Motion-Detector/dp/B000KL0QPS
I've had the double decker GV bolted to an old metal sewing machine frame that I use as a "tactical nightstand" (with mag light and fire extinquisher also mounted) for 10 years. I've changed the batteries twice during that time and it has ALWAYS worked perfectly. I keep a loaded revolver on the top shelf and can roll out of bed and pop up armed in all of 3 to 4 seconds. I also stowe my carry piece in it's holster on the bottom shelf when I'm not wearing it.
This spring, I picked up a second GV, this time the small one, and I keep it bolted to an 8"x8" Oak beam in a central location on the ground floor. I keep a 1911 in condition 1 in this one.
Kiddies know that the GV is were daddy keeps his guns, and don't even look twice at the thing. They also know that they should never touch or play with a gun, unless under daddy's supervision.
I gave a mechanical lock box similar to the one shown in the link by Sgt_R to my BIL years ago at Christmas time, but I have to say, I like the GV much, much better.
Long guns are in a Stackon RSC bolted to the wall in the basement. Every firearm is under lock and key, or in my immediate controll, 100% of the time.
Keep that little girl safe... get a GV and don't look back.