Rear cup holders

[warren]

I'm looking to add rear cup holders for the kids.
http://www.justkampers.com
All I've found up to now is these, has anyone had any better ideas/successes?

 

[Scruffy]

Try Amazon. They are all pretty similar in design, and a bit crap actually, but I haven't found anything better for the money. Though the solid metal ones are "solid" the rattle like hell; stay away.