Pipe Estimating

Can you add a "Linear with Diameter" measurement type for pipe estimating? Also, add GL (gallons) to the Volume>Units dropdown? I need it to calculate pipe volume as well as linear feet.

This would be very useful for estimating process pipe installations. Specifically, for calculating testing and purge volumes. I think I have a work-around at the item level for now, using a simple formula. But it would be much nicer to see it at the takeoff level.