Cyclone III matching footprints

[Altera_Forum]

I am in the process of helping my board layout guy to plan a design for a Cyclone III board. My project director wants some flexibility in the logic block count for the FPGA, in case we get further along in the development cycle and need to go to a higher count part. 

 We were looking at the 484 pin FBGA since it appears that footprint will accommodate 55k part (which we are designing for) and 120k part (which is the backup plan). But it seems that some power and ground pins are moved around from one part to the other.  I'm assuming this is a deal-breaker, since we'd have to lay the board out specifically for the 55k or 120k part. Is there any way to work around this, or any other combination of parts above 55k that would enable us to have insurance in case our final design doesn't fit into the 55k Cyclone III?  Speed grade and number of I/O pins do not matter.

[Altera_Forum]

For a single board layout to support more than one device, select all devices in Quartus. Select one device the usual way. Then on the Device page of the Settings dialog box click the "Migration Devices" button to select the other device(s). Quartus will provide a pin-out that will work for all selected devices. 

 According to Quartus, EP3C80F484 is an available migration device for the EP3C55F484.