I own one. The full model name is RG7-680 LTD1.
There is a blueish-gray model (as pictured above) and a dark red model. I tried to find out more about it and wrote to the Ibanez distributor here in Germany, but they even didn't know it existed
Here's what I found out during my research on the web: Built in 2000, they were very limited, something between 24 and 100 instruments exist. It was a small production run to find out whether people have a demand for 27" scale 7string guitars or not. They did this a few times in the past, think about the first piezo models that are rare as hell. They used very good woods on this and you can see and feel that. Actually, the test runs they did after the 7680 were all labeled J.Custom, just a thought...
They came with the DiMarzio New7 Pickups that were standard on the RG7620. They have a 5-piece neck with two thick dark stripes (Maple, bubinga, maple, bubinga, maple) as later J.Customs have it. And guess what, the binding around the body and neck and the headstock even glows in the dark!!!
So do the dots in the fretboard, it looks really pretty cool. Just a few minutes in direct sunlight or blacklight and you have this cool effect for hours.
Here are some pics if you might want to take a look at mine:
Any questions, just ask!