Seems to be impossible to find. I have checked on ebay and other auto part stores, and only type of hood latch I can find is for the Cherokees and Wranglers.
check your local auto dismantler or auto junkyard
just do a local search on the web
give the business a call
usually they will pull the part out for you or bring your own tools to pull out yourself
If the latch for the regular Cherokee and the Grand Cherokee are not the same ( and it would seem that they would be) then a wrecking yard may be an option for you