Napodano's line is a tough one and probably appropriate in many countries. It's also consistent with Robert Barro's line: he suggests that temporary tax cuts are the best form of fiscal stimulus (perhaps borne out by the VAT cut - now reversed - in the UK?). If we go back to Keynesian multipliers though, we should remember that tax cuts are less effective than direct public spending - theoretically at least.
The new head of the IMF is, however, suggesting the need for further fiscal stimulus in those countries that can manage it (probably her comments are aimed at Germany, but the 10 year cost of borrowing for the UK Government is also at or near an all time low - a result of fiscal prudence or excess saving?). To quote Christine Lagarde (my underlining):
Debt-reduction strategies must be based on concrete and substantive commitments not just words but the impact on the economy can be set with a delay. Policy actions can focus on areas where the pressure is mounting tomorrow, but have little effect on demand today such as reforming entitlements or restructuring the tax system. At the same time, short-term measures must be supportive of growth, yet economical in terms of the impact on fiscal sustainability, and can include policies supporting employment creation, advancing planned infrastructure and easing adjustment in housing markets.
How do you advance planned infrastructure in a hurry if projects have not been thoroughly prepared? Not easy, particularly as Lagarde is also emphasising the need for fiscal tightening over the medium-term ('Goldilocks' fiscal policy as she calls it - not too hot and not too cold). The 'hump' in infrastructure spending could therefore come at exactly the wrong time if it takes too long to pump up the scale of the programme.
Practically speaking, it's very difficult to press the accelerator on infrastructure in a country like the UK, where meeting the requirements of planning laws is usually the key to the pace at which projects can be implemented and not fiscal constraints. I also doubt that there are many opportunities for increasing the pace of implementation of a multi-billion pound multi-year scheme like London'd Cross-Rail - engineering considerations will now be driving the timetable more than financing.