First, you steal 2 very high quality line level audio isolation transformers.......
The isoMax contains 2 Jensen isolation transformers. Looking at the prices for the transformers alone, they're not charging you all that much to house it and make it practical. But depending how you value your time, there are cost savings to be had.
You can source, "equivalents" to the isoMax from ART, EDCOR, etc.... or source your own transfromers from Jensen, Cinemag, Edcor, etc.... and build.
Hopefully, Steve Eddy will weigh in.