Sorry DonM, but you got one thing wrong: the G-70 indeed has a break button.

[The OS2 features a break mute function for the ASSIGN SW buttons. The function can be accessed via the ASSIGN SW button you assign it to. When you press that button, Arranger playback is muted for the remainder of the current measure. This feature is known from older Roland arranger models and has been requested by the Roland G-70 User Club Denmark members.]
http://www.selskabsmusikeren.dk/index.php?option=com_content&task=view&id=253&Itemid=28

User Club moderator Diki Cox had via the user club forum put up a request for a "break/mute function on the footswitch and FC7. When Roland release the OS2.02 they implemented this feature too.

So as you see the G-70 certainly has a break button

NB. About the weight: open the cabinet and remove the bricks mounted inside =