Quoted:
Have you thought about a safe?  The rifle will still be locked and not any slower to access, but its out of visibility.  Keeps your little girl from getting curious as to whats on the wall.

Quoted:
A Santa Cruz universal gun lock holds my Mossberg 500 on the inside of my closet wall.  I use the buttplate and L-bracket to keep the entire assembly about 36" off the floor and out of reach of my young kids.  This also does a decent job of hiding the gun behind clothes.  If little fingers ever reached the gun, and somehow there was a chambered shell, the end of the barrel is about 6' up, so the only damage would be a hole in the ceiling/roof.  Their products are a lot beefier than they look in the pictures online, and I was impressed with their quality.  

The only key is on my key chain.  At night, I insert the key in the lock.  If I need the gun, access is fast.  In the morning, I remove the key.  I cannot forget to remove the key as I can't start my car or lock my house without it.

As an additional measure, my house alarm has a sub-alarm system for medicine or liquor cabinets, etc.  That sub-mode remains armed even when the main house alarm is disarmed.  I have a small project in mind that uses this sub-mode and would result in the home alarm being triggered if the gun is removed from the rack.  I cannot think of a situation where I would need the gun where I would not want my interior and exterior bullhorns at full volume.  My goal is to get an intruder out of my house and defend my family - not to sneak up on one and corner him. I can also disarm the sub-mode if I just want to get the gun out of the rack to go to the range, etc.

Another project might involve a hidden switch in some trim to allow key-free access to the gun.  I just need to arrange a 12v UPS to power it.

In talking with them, I believe they have a new lock in the works specifically aimed at the home market and will eventually make a push to increase their market share of non-LEO business.  Last I read on a forum (forget where - sorry), I think it was to use a key fob type of unlock mechanism as one option.  They were being very careful to ensure the new product line was perfect prior to release as liability risks are a lot greater with the home market than with the LEO market.

Hope that helps.

Quoted:
Afraid that"s all the info I have.  Last time I called they were very nice and helpful, so if you are interested, I would definitely call and ask.  They outlined the system in some forum, so it should not be a secret.  

Some good info here on powering the existing system if you do not/cannot wait for the new one to be released:

http://www.shotgunworld.com/bbs/viewtopic.php?p=1220830#1220830

In my case, I had to get the gun secured ASAP, so waiting was not an option.  Let us know if you find out more - they make good stuff, and I think the home gunlock niche is far from full.

Good luck!