I am looking for parts catalog piece to display an underground storage tank with manhole access point(s).  Tank is cylindrical with varying length and diameter.  Tank will have multiple MH access points.   AutoCAD 2011RMRichardson2012-03-30 17:25:18

Sounds like you should be using a Dynamic Block.

Have you tried Autodesk Seek?  Either SEEK at the AutoCAD command line or http://seek.autodesk.com/Dave