Hi Amy,
I invite you to consider our UberCalc solution, which is designed for precisely this kind of aggregate and store at a higher level requirement. Once the aggregated data is in place, you can then use in a myriad of other ways, such as sorting parents, calculating % vs parent, highlighting children (in red) that are less than the average of the parent, etc. On the Agile side, the closest I'm aware of is the recent improvement to add Small, Medium or Large Work Estimates you recently mentioned, but at this time, there does not appear to be any further development in that area.
Combining these two ideas, though...
I've recently been mulling over the concept of treating abstracted Work Estimate (e.g. T-Shirt size being the classic example) as if they were a different time currency. The concept of a currency exchange, whereby at any moment in time one currency can be converted to another as Things Change is well established, and -- with my Finance background, unavoidable -- it strikes me as inevitable that at some point, whatever unit of measure is being euphemized for convenience / obfuscation, it must at some point translate to time.
Following that logic...
I'm further imagining an "exchange rate" for time (and -- gasp -- perhaps even maintaining it within the the available but often unused Exchange Rate feature within Workfront) to set up a translation of T-Shirt Sizes to Hours (e.g. Small = 2 hours, Medium = 4 hours, Large = 8 hours, etc.). With that data then available (and noting that it could be expanded to include the Extra Small and Extra Large concepts you'd proposed, and that the actual "rates" could change over time), UberCalc could consult the current exchange rate, calculate the appropriate hours, and store them in the appropriate place within Workfront to thereby then take advantage of the many aspects of Resource Planning that are based on that universal currency of time...including our Resource Contouring solution, which we could even adapt to show using T-Shirt icons, instead of hours, if that is more useful to those doing the planning.
I (and I suspect my colleague @Kyle Silberbauer - inactive‚, with whom I've been Blue Skying on such matters) would be interested in your (or anyone else's) thoughts on whether this sounds like a road worth travelling, either here on this post, or via email at doug.denhoed@atappstore.com
Regards,
Doug