Dogs and bike-riding (looking for a new harness)

I've been looking at various harness setups that allow a person to safely take their dog along on a bike ride. I have theSpringer brand harness/bike bracket and it works OK-the only thing is that I'm fairly short and usually need to keep my bike seat in the lowest postion. The Springer attaches to the seat post and raises the seat up about 3 inches or so and then I'm up a little higher than I feel comfortable with (I like to be able to touch the ground!). There are a couple different brands that attach to the back wheel assembly instead. Does anyone have any experience with these set ups? My dog needs the exercise (and so do I!) I'm looking at a new bike for spring and think it would be fun to take my buddy along with me.
Thanks!
Deb