I'm not sure about the frame and front end differences between the NBS (00-06) and the NNBS (07-current) Tahoes, however the guys over on TahoeYukonForum.com will point you in the right direction.
I have a Hidden Hitch Font End Receiver (part no 65023) for sale on craigslist ...
http://sacramento.craigslist.org/pts/2837241787.html
The install for me required drilling two holes in the frame and then cutting the lower valence to allow the receiver to pass through. On my Tahoe, the spot where it passed through was slightly lower than the license plate so a flip-down plate would not have completely covered it up.
Hope whatever it is your working on goes well for you ...