Quoting TheyCallMeMOMMY♥:" Have you tried old navy? They have them in the tall section, Im 5"10' too and they fit me great! Even after my pregnant belly takes over! lol"
I tried on some old navy... last year at least a lot of them were strapless or spaghetti straps... I never ordered online though.
Mostly because when I ordered old navy "tall" jeans, they weren't long enough for me. I'm literally all leg lol so I was afraid the dresses would be the same... but i guess dresses are different than jeans.