I am hitting a bit of a hard spot here, and wanted to see if anyone had any bright ideas.  There is a limitation of the basic functionality of roll-up summary fields to use filter criteria from a formula field containing cross-object references.  This has been referenced on idea exchange (link below) and has documentation expressing the limitation, "...system fields like Last Activity, cross-object formula fields, and lookup fields (such as the Product Codefield) cannot be used in the field column of roll-up summary filters."  I understand it would be possible to get what you need into a report that performs the function, but if the value will be used in a communication template, that is not a viable option.  Workflow rules would also allow the field to be replicated to a standard field that could be used in a roll-up, but they would only be relevant if it was assumed that all child objects would be modified at some point prior to action of requiring these values.  As some of the data could be already present, that is not optimal as well.

Has anyone else experienced this frustration that would be willing to share a solution?   Or has anyone found a method of getting an aggregate sum of objects to output the total value into a visualforce page?  I am at a bit of a loss of exactly what is required to try and get the equivalent of the roll-up into a communication template, so it is more then possible that I am going down the wrong track.  I would assume that the best option would involve an apex class related to something else that would not require a triggering action.  Any advise or corrections would be appreciated.

Thanks!

Idea Link: https://sites.secure.force.com/success/ideaView?c=09a30000000D9xtAAC&id=08730000000Bra0AAC