I pushed some Aconcagua extensions to http://smalltalkhub.com/mc/SeanDeNigris/AconcaguaAddOns/main/ One part consists of tiny (so far) Aconcagua models of various domains - Time*, Money, and Weight at the moment. The other is the Aconcagua-Magritte package. This gives you MAMeasureDescription, which represents an Aconcagua Measure. It mostly acts like a number field mapped to its amount. You just have to tell it which unit to use to convert the amount number into a Measure. Example usage: MAMeasureDescription new accessor: #replacementPrice; label: 'Replacement Price'; unit: AmDollar new; yourself Then, you can type 100 in a Magritte form and "100 dollars" will be saved to the model. Enjoy!