Activists seek Canada Tax Gap Estimate

There is a movement afoot to get Canada to get on the "Tax Gap" bandwagon, and make an estimate about how much is lost in tax revenues to tax evasion. As far as I know only the US and the UK even try to estimate this, and the UK's estimate has been criticised as laughably low, while the US estimate is hampered by shoddy data. Still, it's an exercise worth undertaking I think. If the government won't do it, do we have some enterprising accountants or economists willing to give it a go in Canada?