i just finished making one.
i found it at
www.rockingtranch.com/i always follow up on a link i post and it seems the link on the page is common for the whole site.
its a good cheap brooder. if you want to find it, click the above link. next click the logo, scroll down and look for the "tour the farm photo pages" (third row of links,left end. scroll down, click "our hatchery" (right side 5th row) your there.
i just started with the single version mentioned in the end