*sigh* anyone looked at the progress of Stock by attributes recently? While not recently revised/written for ZC 1.5.0, it just might work if you use SBA version 1.5.3.

https://github.com/potteryhouse

I know I certainly would take donations to continue the work that I have been doing to build off of what potteryhouse and jeking set out to accomplish.

As for multiplication of attributes, I have something that accomplishes it to one degree on my site. It could be expanded upon to multiply in larger factors/groups.