Seanie
First, a clarification I hope I do not bore you with: The application to control AppleTV with your iPhone / iPod touch is called "Remote.app". You can download it for free from the iTunes Store and it is being installed on the iPhone / iPod touch, not on AppleTV. It is the same application that allows your mobile device to control the iTunes application running on your PC/Mac.
To work correctly, your Phone / iPod touch must have a Wifi connection to the same Ethernet subnet as your AppleTV is in, which at home is not a big issue as you most probably will have ONE subnet anyway. So, given your Phone / iPod touch "sees" your AppleTV, it will enable you to select media content to be played - and will display the content info on the display of your Phone / iPod touch.
If you have two mobile devices running Remote, both will display the content info, and both will be usable to control the AppleTV simultaneously. Your lounge / kitchen example will work ok, if you are willing to take a waiting time of about five to ten seconds to switch your iPhone / iPod touch on, connect it to Wifi, find the AppleTV and display the content info.
I think, the limit of five remotes quoted on the Apple website is not for the use of iPhone / iPod touch, but for the use of the small white Apple infrared remote, which has no display. The number of Phone / iPod touch devices connecting to the Apple TV is theoretically only limited by the number of available IP-addresses in your network's IP-subnet, best case 253 devices.
Could you restate your question regarding wall mounts more clearly? Would you like to mount the Apple TV nicely or the iPhone / iPod touch remote?
Best regards
Stefan