The payroll templates (I'm in Aus) are fantastic to be able to develop employee by employee and then import into your budget. A fantastic tool would be to expand on this for on-costs - namely state payroll tax and workcover. Payroll tax is different in each state as to when it kicks in and what rate, and many clients have employees in 2 + states, so to be able to calculate would be awesome.
We are currently looking at how to bring the payroll template functionality in app, at which point we will be able to look at adding in additional features and expanding what we can provide. This sounds like a great idea and I shall add it to our backlog.