I'm in the same boat as you. I currently use a 8' bale ring. I have been lookingat some type of hay saver for the last couple months but haven't pulled the tripper yet.
I like the looks of the J & L Haysaver
http://www.jlhaysavers.com/our-products.html It looks like there list price is around $1,100 if there website is accurate.
I also called Steinway
http://www.steinwayequipment.com/bale_feeders.html Their 8'x8' feeder was $1,385
I drove by a local dealer the other day and noticed a feeder similar to the J & L, it looked to be galvinized though with a tire base. There price on it was in the $1,100 range also.
I'm having a hard time justifying the cost for my small herd.
I know someone who has a J & L and they really like it. They said it really cut down on hay waste. My neighbot made his own cone type feeder out of a regular bale ring & some old freestall barn dividers & it works good for him.
I'm still leaning towards trying to make something up myself for now just to see how I like it. I need to see what I have laying around though.