Need a Sugar Free Cupcake Recipe

I'm going to a party Friday and I wanted to make a sugar free cupcake that is so good they don't know the difference.  I've been googling for a while and can't seem to come up with anything.  Sometimes when I just substitute the regular sugar for for splenda, it doesn't always fluff up the same.  Does anyone have one they could pass on to me please?

I recently made cupcakes with Duncan Hines devil food cupcake mix (got at the Dollar Tree) and 1 can of pumpkin.  Mix together put in muffin tin & bake 350 for I think it was 18 minutes.  101 calories for 12 or 52calories for 24 mini cupcakes.   I've also made them with PB2 mixed in ~ yummy!! 

It's probably too late for you, but this is what I do:

Mix 1 box cake mix with Splenda (any flavor you wish, I like chocolate) with 1 can of diet soda (I use Diet Rite cherry cola), then put in cupcake pan and bake according to box.  I put 1 dollop of SF cool whip on each one.  They taste awesome and are nice and dense but rise nicely!

I have used white cake with diet orange soda and white cake with diet red pop and both turned out awesome, the possibilities are endless!

Boxed cake mixes have sugar in them don't they?

Pillsbury makes a reduced sugar mix