This poses a new question for the accountants, and could be a very nice incentive to order one just for this purpose! Thanks for starting this thread.
This one uses 6,000 lbs GVW, so the Grand wouldn't qualify:
"SUV’s and any 4-wheeled vehicle designed or used to carry passengers over public roads with a Gross Vehicle Weight (GVW) of more than 6,000 lbs and not more than 14,000 lbs (see below for limits on these heavy SUVs)"
I couldn't find any mention in the IRS publication of a cutoff weight at the bottom, but they do mention those above 14,000 lbs do not qualify: