Remember those old Stack Hat bike helmets you used to wear in the 80's late 90's..where can i get one from??

Yes I remember them.
For a while it was going to be a choice between wearing one of them or not riding a bicycle in Australia. Fortunately somebody had the sense to ask some cyclists why they did not want to wear them. (The Half pipe guys seemed to love them) The designs started resembling the modern cycling helmet from about the late 80's.
Here's a few piccy's from the net showing them in all their glory.
http://www.powerhousemuseum.com/collecti...
http://flickr.com/photos/tags/stackhat/

Apart from the "original" helmet Rosebank kept the name stackhat for several models including the "Microlite" circa 1990 which is quite similar to modern helmets
http://www.rosebankhelmets.com.au/roseba...

It was only a few years earlier that some cricket players started going in to bat wearing motorcycle helmets. The cricket helmet developed quickly from there. It gained acceptance quite quickly, mostly because the players were involved in redesigning it to something that they would use. (It doesn't look anything like a motor cycle helmet these days.

Yes they do come up from time to time on ebay (rarely). Keep in mind that they do have a service life and have been out of production for significantly longer than this. (recommend as a display item only)
http://cgi.ebay.com.au/Retro-stackhat-80...

eBay eBay eBay!

Good lord. Why would you want one of those things?