Pak 128 has similar so I made one for pak Britain
I recycled old graphics and here are results.
There is mailbox only one side of road like in loadingbay/mailbox but should it be on both sides?
http://www.saunalahti.fi/jusskiiv/pak/bus-stopwithmail.zip (http://www.saunalahti.fi/jusskiiv/pak/bus-stopwithmail.zip)
(http://www.saunalahti.fi/jusskiiv/img/stop.png)
I think that it looks better with the mail box on only the one side of the road.
I like it - makes them easier to find than just the sign, but not too cluttered.
This is now in the pak :)