is this possible?

Forget about that. It is impossible

Will there ever be an update for this unit?

there will probably be a 2013 map update for z110-140 and x920-940, however it remains to be seen if there will be any UI updates to make it similar to z150/x950. 

The map update will probably come in August or September timeframe given Pioneer's update release history.

The new platform is completely different hardware (a big change from previous iterations), with a completely different cpu architecture (arm vs sh4), so z150/x950 code/apps will not run on previous versions - sorry.

I put my bet on no-way-in-hell will they release any major UI update on existing platforms. This would remove incentive to sell new units and hardware. 

sh4? Ooops. Game over...