triumphess, i posted an answer on RV.net hybrid forum.
but, i did think of another solution.
i am currently using a ball-mount folding bike rack from Swagman. it bolts to your Denali's rear step bumper, in the hole for a ball. here's a pic:
i got one off of Ebay for about $60. it should hold the bike high enough to clear the battery on the tongue. i use it with two bikes on my '07 Avalanche, which has the same step bumper.