Recommendation/experience with beach rollers?

[Porter Wayfare]

I need to be able to get my centerboard dinghy on and off a beach--maybe a rough beach.  I once saw some Italian made beach rollers that looked pretty tough.  I can't find a source for them now.  The dinghy, laden, will be in the neighborhood of 600 pounds.  The rollers would be used in conjunction with a block and tackle.  Any ideas?  The thing about rollers is that they are longer than bumpers and so are not so hard to keep under the boat.