I have an idea. How about sellers be more transparent in their description and ebay force them state any profits they make off shipping as profiting from shipping is against ebay policies. If you want to play symantics and hide them under "Handling fees" then you are already playing the dirty game and deserve what you have coming. Atleast this way buyers are not left standing there wondering if there was any miscommunication?
The card industry did this with the "All in pricing" so that way there were no hidden costs and everything was broken out.
Following this method, a seller should put in the description how much shipping is, how much they are going to profit off you.. for example..
Actual shipping costs: $2
Supplies : $2
My profit: $2
Total shipping costs will be $6 eventhough your postage paid will be $2.
Pretty cut and clear. If you have nothing to hide and are confident tbat bidders dont mind, then state it. Stop playing games and be transparent about it. Otherwise while you play the system to make a profit on misconception, bidders will paly the same system by penalizing your feedback for it.