My boyfriend's mom is getting married and she and the groom have health issues and will need a Splenda cake. I'm thinking I can do the top two layers Splenda-fied for them (one for 1st anniversary, one to eat that day) and the rest regular. They want marble cake with some sort of vanilla cream filling. What are your best Splenda cake recipes?

Also, is it possible to make pastry type creams with Splenda?