[rab] I've got a BT Quartet system which I bought about 4 years ago [though mine is only the 'duet' version because I didn't see the need to buy 3 handsets]. The base station with aerial plugs into phone point and power socket down here in my kitchen/officy place and the portable handset sits on its own charger which is plugged in upstairs in one of the bedrooms. The phone itself often gets lost in one of the bedrooms but appears to keep its charge for days without sitting it back on its power plinth. Very handy - it's even effective from my friend's house which is a few doors down the road.
[Chalky] It's more of a 'monet' that I'm after: base station + 1 handset + charger separate from the base station (as the base station has to sit in a place where I don't want to put the phone to charge).