I guess this will be as close to a complete rainbow as I'll probably ever come. It helps that there were only four cards to chase.
Archives had a base card and a gold parallel. Four printing plates from the base card were also available. Finally, there was a day glow orange parallel for the first 200 cards in the list.
They were found in special 25¢ five-card packs of Archives that were exclusive to hobby shops the week of June 10. You could buy these packs when making any other Topps pack purchase. These special packs had four base cards and one day glow orange parallel. Though not numbered, I can't imagine that there is a very high print run on the orange cards. Anyone hear an actual number?
I was able to get a real bargain on my orange card....it set me back all of 54¢ plus shipping. I think I got a pretty good deal!