A mate of mine is 5’5″ and has a 14″ Inbred, my lad is now 5’8″ and is on a 16″ which he has only just grown to fit on properly – they are pretty long.
I had a thread running which seems to have vanished when I was looking for a bike for my wife who is 4’10”. Lots of suggestions about the XS Spesh, Trek, Marin options. Very rare that a decent spec bike comes up for sale in those sizes, but if you have the parts already, original spec doesn’t matter. (The fact that I haven’t got her anything yet is entirely down to her and not me or the bikes!)
Also a few decent 26″ wheeled bike available now being marketed as “kids” bikes, as they have that tiny weeny 26″ wheel thing going on.
Agree that lighter wheels and tyres will make a huge difference to how any bike feels. And after some bargain hunting on here, a pair of Easton Carbon bars (£20!) and an old carbon seatpost of mine knocked almost 500g off the weight of my lads Inbred,