If you want a cordless perhaps the Oreck Pod?
I know you want clean filtration and simplicity and I feel like you might like the Oreck Pod cordless stick if you want something simple to go around with. They are a direct air and have hepa bags, so I feel like there would be less to get stinky since it's not a bypass system. Another cordless option would be the Hoover Onepwr, cordless direct air HEPA bagged vac but I don't know how good it is on hard floors but they do advertise it for hard floors. I know you have your reservations with Hoovers but the Onepwr stuff isn't horribly expensive and it doesn't seem to be terrible although the reviews on some of it is mixed. There are also some higher voltage commercial cordless vacs that may perform a little better but at a higher price. You may not be interested in these but just a few thoughts if you did like having a cordless vacuum.
