Omniscope supports multi-variate real-time modelling/simulation using user selectable Variables incorporated in formulae. See the embedded Human Resources demo Dashboard Tab for an example. Currently, formulae can only reference other columns in the data sets, rather than rows.

You can do this in Omniscope by creating a formula field and a variable. The variable would appear as a slider in the right-hand devices panel and would represent the growth rate. The formula would multiple some other field's value by the slider's value to create the simulated volume (or price, or quantity). Dragging the slider would cause the field to recalculate, and, if that field was used in your views (such as a Graph view Y axis), the views would update.

You could then create different tabs for different growth settings. Each tab retains its own slider values for variables. You can also add annotations to each tab to comment on the result.

See http://www.visokio.com/defining-variables for more help with variables.

Thought it was possible, just needed pointing in the right direction. Thanks for both responses.