The Piaggio is a neat airplane: we see a couple per month. It works well for a business airplane, but it would be difficult to adopt this design to a much larger commercial aircraft. If you are talking regional prop similar to the Q200 or Q300, there remains the possibility that it could
work. However, that would mean more than doubling the length of the aircraft which would add more weight; adding more cargo room which would add more weight; accounting for the added seats and passengers (more weight again); and other improvements to the airframe and systems. This would require a more powerful powerplant, one which is likely not yet in production or cannot be fitted to the Piaggio's design. The max weights on the current Avanti model, even translated into an 80 foot long airframe, would not be nearly enough to sustain commercial use.
The other difficulty comes in receiving enough of a response from airlines to launch the product. Couple of factors working against them. There does not appear to be a huge market for turboprops right now, although the tide could be turning. If the market does turn, there are established airframes available that fill the void very capably. Plus, with the lackluster sales of it on the business market, the company is not in a strong market position to create and market a new commercial airplane.
I like the Avanti. It is a neat, fun airplane for light business use. For commercial use it would basically have to be a completely new design. Therefore it is highly unlikely that the Avanti will be developed into a commercial airplane in the forseeable future.
The Q400 is receiving some looks from airlines looking to reduce fuel costs on regional routes, but even it's sales are not great. That might change in the future, though. Check out the information on Bombardier's website about it