4g61t.org

Google search for 4g61t pistons - fifth entry down yielded this result:

https://www.google.ca/#q=4g61t+pistons

http://www.rpmmachine.com/shop/index.ph ... ail&p=5112

They sell a kit with 4g61t pistons. I'm sure you could order the pistons only.

Also checked out partsdinosaur.com but they only ship to the US/US Zip code.

Or the best option out of Australia with a major expensive price tag - but likely wicked stuff:

http://www.rpw.com.au/shop/index.php?pa ... 1&Itemid=3

There are more places to look, and some places will make a custom piston. I believe a member here just had a set made .....