kp just posted his BigAssCanvas class and I thought I would link to the post here.

http://www.bit-101.com/blog/?p=1199

Basically it allows for creation of larger bitmapdatas. Currently we are limited to 2880x2880 this class can create a large BigAssCanvas that stitches the BitmapDatas together and also alows many of the same functions as the original BitmapData.