I agree with melissa, how much excercise is a lot, and how much is low is a matter of opinion. I have a 19 month old male german shepherd, imported from belgium, bred of german showlines, and a little german working lines. (first I will explain his typical day before we got his baby sister...a 12 week australian cattle dog/blue heeler) he got 3 walks a day, plus play in the back yard, plus play inside the house. his day started by going into the backyard to do his business while I got his food ready. he would chase the squirrels up the 2 trees and then run back and forth all over the yard looking for a way to get to them; then he would eat his breakfast; come back inside and get a lot of attention and not really excercise for about 20 minutes while digesting; go for a 1.5 mile walk around the neighborhood; spend the rest of the morning chilling out, playing with his toys, and would maybe have one running fit around the living room and kitchen (figure about a 1/8-1/4 mile worth of running), and about every hour or 2 a trip outside in which he chases the squirrels again if they are back; at about noon he gets another walk...usually 1.5-2 miles; then repeat the morning in house and back yard activities; dinner at around 5pm and repeat the breakfast ritual; about 20 minutes later another walk usually 2-3 miles depending on how tired daddy is; repeat the in house and backyard activities untill around 9-11pm. 3 days a week and saturdays he goes tracking in the fields and woods about a mile or two away, during tracking he walks anywhere from 3-6 miles through cotton fields, corn fields, open woods, thick woods with a lot of brush and thorns, across 4 creeks (really 1 creek in 4 different places with varying steepness of banks and depth of water), across a rope and board bridge (the owner of the property loves to tag along and was nice enough to build it as a suprise for us), over a huge pile of rubble (concrete, boards, iron rebar), and then through a pasture with about 30 cows and a huge black angus x longhorn bull, through the stable and to a different ending place evey time (and a different route everytime).
this past saturday afternoon we rescued a 12 week old female australian cattle dog. so basically striders excercise is the same, but now he rests in the house a lot less and chases and gets chased by the little girl. he goes in the backyard a lot more due to her frequent potty break needs and everytime they go out (about every 30 minutes) they run like crazy and chase each other. so his routine has changed in that she provides him with about double the excercise he used to get.
so to me, what you descride is very very low excercise requirements. but I also understand the fact that too many people here your description probably seems very very high. its all a matter of opinion/perspective. Im not saying that from what you describe you wont be able to provide adequate excercise, I think its possible that you may need to provide more...but you describe more excercise than many owners even think about providing. I just intended to show you MY perspective, and why I think and probably why melissa thought you were describing somewhat low excercise.
the dogs you are considering do have lower excercise needs, not extremely lower, but enough. but just be prepared, you may have to increase the length or frequency of walks and Im sure you are but be prepared to do a lot of ball or frisbee throwing in the back yard.
and good luck!!! I think all the breeds you mentioned would be great. personally I prefer the bernese but I may never get one due to the shorter life span.