multiple units of measure per item?

We are deciding whether to do a trial installation of FA.  From our reading so far, one serious issue is our reliance on multiple units of measure per inventory item. 

So I would like to describe what we do (and want to replicate),  and solicit information about how to do it or use the abilities of FA to do substantially the same.

Here's the situation:

My client makes (physical) windows.  Every window is a custom item (no assemblies, stock dimensions, etc).  Thus, we use a vertical-market configurator that tells us how much material each window (order) consumes.  This is aggregated and removed from inventory (with appropriate waste factors) on a daily basis.

We have decided to retire Accpac Plus DOS  (yes, there are still companies using it!). Unfortunately, we rely on the fact that it supports 4 units of measure for each inventory item.  This is a necessary function for our operation.

By way of example, our configurator software calculates usage of glass in square feet and we take it out of inventory using this measure.  We purchase it by the case, each of which has a certain number of sheets (each type of glass has a different number of sheets per case).   We count the inventory in sheets and cases (when we reconcile the on-line inventory to the physical).

A more complex example would be aluminum extrusion.  We measure and use it in feet when manufacturing.  We purchase it in kilograms.  It is received in bundles of X pieces (each type of extrusion has different number of pieces per bundle), and we count it in inventory in both bundles and pieces. 

Accpac accepts input in all the defined units of measure and calculates the value of the inventory appropriately.  The purchase order for glass would be in cases, and for aluminum extrusion in Kilos.  The inventory is relieved of product in square feet (glass) and feet (extrusion) respectively, because the configurator software has no knowledge (nor should it) of the various other measures possible.  At inventory time, we adjust the inventory to actual by entering both sheets and cases (glass) or feet and bundles (extrusion).

Many years ago (before Accpac, approx 17 years), the error rate on inventory management was horrendous (as you can imagine, depending on humans to know and make the conversions). That problem disappeared, and we really don't want to re-introduce it.

It there anything we can do to approximate this?