If you like the mexican flavor try substituting Red Enchilada Sauce instead of diced tomatoes.  If you have a Safeway or Genuardi's in your area they carry a 28oz. can made with red chiles instead of tomatoes.  It is delicious and doesn't have the sugars that tomatoes have.

Does the sugar alcohol content bother anyone?

Yes on the applesauce.  I use xylitol instead of splenda, they both cause some gassiness, but I react less with the xylitol.  The whole wheat flour will make for a dense bread, though.  If you can get it, try whole wheat PASTRY flour, and if you are really willing to fork over some money King Arthur now has a whole wheat cake flour.  I found both at Whole Foods.  Either one of those will make a more tender zucchini bread/muffin.  Finally, if you use any dairy in the batter, try buttermilk (I buy dry buttermilk in the baking aisle, use similarly to dry milk) or yogurt. 

Good luck!

(I'm working my way through several pounds of frozen pumpkin puree and another 5 butternut squash in my cooking experiments.  Found one pumpkin cake recipe that I make up as cupcakes for lunches, but I still can't convince my family that butternut soup is GOOOOD!  Hey, kids, come to the table!  We're having soup!) 

I LOVE YOUR RECIPES! YOUR PUMPKIN ROLL IS ONE OF MY FAMILIES FAVORITES!!!