possible, but difficult:
1) you would have to create different AoEs in vfx_persistent.2da with radius 10', 20', 30' 40' etc.
2) you'd have to modify the AoE-onheartbeat script to destroy the current aoe and activate the next aoe with 10' larger radius
3) you'd have to take care to carry over any spell parameters (dc, metamagic, penetration, casterlevel, location...) from one aoe to the next
4) by the time you destroy the old aoe and create a new (larger) one the association between effects applied by the aoe and the "correct" aoe spellid might be lost. You'd have to take that into account when removing aoe effects (for instance onexit).
I thought about a similar system to implement metamagic enlarge or casterlevel dependent aoe-sizes. Such a system would use some generic aoes of different sizes. The problem with that is, that one needs a generic set of areas (with different sizes) for each different appearance (at least thats my current understanding). Meaning the implementation of metamagic enlarge would require a large nr of "generic" aoes (different sizes, different appearances)