The most compact solution won't be a bag that is sold as a "camera bag." Heavy padding and "compact" just don't go in the same sentence. I suggest that you look at the plethora of bags sold as "tactical bags." I use this type of bag almost exclusively, sometimes adding a 1/4" or 3/8" thick piece of closed-cell foam to the bottom. IMO if you are at all careful in how you handle the bag (i.e., don't let it swing when rock-climbing), padding is unnecessary. Here is a "tactical" bag that I have used for 4-5 years all over the world.... compact shoulder bag ... What's the most compact solution?
+1 for the Event Messenger 100. It's one of the most compact, holds it's shape (easy to load/unload while on shoulder), and holds as much as my shoulder is willing to carry for a day (ie. I'm not tempted to take everything I own in one bag). It's perfect for a m43 with lens mounted, up to four extra lens( I usually carry 2 extra), couple of cards and filters in the front and the side elastic pockets are perfectly made for spare batteries.Thanks for your advice.
I finished up buying the Lowepro Event Messenger 100 which meets my needs at a reasonable cost. See this link;