Okay I'm sorry I cracked a joke earlier about elastic waistbands for XS's. I am 5'0 tall and petite though not child-like these days, just short, as I'm now in my mid 50s. Inverted triangle shape, C cup, hipless wonder. I.e., a size 6p and many size small regulars work just fine, as long as vertical length isn't uber important for the garment, or can be alterable. I totally get the struggle, as I've been there most of my life too, just not recently.
Here are my Amazon recommendations---
I went way back into my orders for you ... like you are probably doing, I spend a shit ton of time analyzing whether a particular garment will work for my height and is worth ordering. It's frustrating and time consuming!
I bought this after many hours reading through all the reviews and comparisons of similar offerings. It totally works lengthwise, especially after running through the dryer for shrinkage. Is it the best quality? Absolutely not. But it fits, without alterations! Not too long.
Also bought this after buying this which totally swamped me but worked for my 20 something daughter just 4 inches taller than me.