ISO Interchange e-commerce consultant/developer

I've got a client with an Interchange-based store based on version 4.6.  
I want to move the site to 5.4.2, and undo a number of hacks and 
customizations to simplify catalog maintenance and Interchange upgrades.

A previous developer customized the product database schema and related 
templates to support SKU-based product variations.  That is, variations 
of a single product (color, size, etc.) each have a separate SKU.  The 
previous developer created a hack "product family key" to link related 
SKUs together, and added an intermediate level of search and product 
browsing UI.

The result is a set of templates that has so much hacked custom code in 
them that they're difficult to work with.  I'd like to work with an 
experienced Interchange consultant/developer to design and build a new 
5.4.2-based system that implements Interchange and e-commerce best 
practices while addressing the SKU-based product variations requirement.

If you have demonstrable experience that qualifies you to begin this 
conversation, please drop me a line.  I'd also appreciate any referrals 
to experienced Interchange consultant/developers you might know.

Thanks,
--Lang Zerner