I usually get 1 to 2 blue runes a day, this week anyway, in towers, with party. Doesn't happen as much solo. My only yellow I got was on the day they dropped. Got one in towers. A lot more color mobs there and you don't have to compete with anyone else to kill them.
H2 is when you unlock runes, so when we get to start farming inferno 2, hopefully we get more blues and yellows. I've only had 1 DRO drop in inferno 1 dungeon, I think magic find% plays a big part in runes, having lower than 120% you get lower quality runes.