this reply is strictly geared toward RF wireless keyboards and mice, i do not know the full implications with bluetooth setups.

pick out whatever keyboard/mouse you want, based on layout - not on range claims. i use a cheap micro innovations keyboard and mouse. its a keyboard with good tactile response, and the mouse is full size. its not backlit, but thats not what i needed. AA batteries last for over a month of daily use.

HERE'S THE IMPORTANT PART:
most rf keyboards suck on range due to many variables. here's how to correct that.
when i first setup my living room pc, i had to have the rf reciever sitting on the end table next to me, that meant usb extension cables unrolled all over the floor. the keyboard would only work from 5 foot away - but no more.
tools required: scissors
materials required: left over 2 strand surround sound satellite speaker wire (cheap, thin, and poorly insulated)
optional materials: scotch tape
i wrapped 7 wraps of the speaker wire around the rf receiver, using tape to hold it in place. i left a length of the wire hanging loose off of receiver after the wraps. i set the receiver behind the tv, and tucked the free end of the speaker wire around the base of the tv stand. you cant even see it - but the keyboard works very well from 20+ feet now.

i didnt believe it until i tried it. dont shell out for a high dollar keyboard just because of range claims. buy the one laid out like you want and boost it's signal.