Thanks for fixing the issue.
I do think BigTIFF would be an important feature, especially in the digital pathology arena. When we digitize slide samples the file sizes can alot of times exceed 4 gig limit of TIFF. I noticed you were using a version of libtiff from the output of hdmake, here's a link to an implementation of BigTIFF with libtiff:
http://www.aperio.com/bigtiff/
Kind Regards,
John