Extract thumbnail from file with applescript

When you save a Illustrator or file out of photoshop, you get the option to save a thumbnail. Can I use a OSX applescript to extract this thumbnail so I can place in else where? I don’t want to create a thumbnail from the file as our files range in size up to 2Gb (even the illustrator files can get that big)
In OS9 there was Akua Sweets with “Thumbnail image” Event Class: Get/Set the thumbnail of an image file or picture.
Is there something like this for OSX?

Thanks for any help.

You can try “create thumbnail icon for”, from Kanzu’s Extra Suites.

I have tried it, only one problem it “creates” a thumbnail, have you even got portfolio or similar the creat a thumbnail from a 2Gb Illustrator EPS file? (or any complex Illustrator file) if it doesn’t crash it takes forever. These files already have a Thumbnail in the resource fork (I think that is where it is kept).
Portfolio has an option to use attached thumbnail or create one, so I just want a way to get to the thumbnail already made.

If there is no way to do this atm, I could try to get a OSX script to run a OS9 script to use the Akua Sweets to get the thumbnail.