It was over 2 years ago because it was before i started planning my 1uz project for my supra,
another idea could be to modify cone engineering's 4 into 1 collector kits by splicing half of one into a second full one that is split and stretched.
They list a 5 into one and some odd shapes, you might want to call them and see what they can do or have planned for a 6 into one.
http://www.coneeng.com/exhaust_system_kits.html