My bench is a 3-metre-long section of kitchen worktop (scratched, so being sold-off cheap) supported on five legs made of 80mm fencepost painted matt-black for effect.
To connect the posts to the worktop I used the "bolt down" fence supports - these sorts of things -
http://www.ironmongerydirect.co.uk/p...t_shoes/485009 - with coach-bolts through the worktop. it's strong and stable enough to support AR88s and RA17s without problems!