I pitch on cakes all the time. I love it. Definately go smaller beer to bigger beer, and also be aware that you will probably never be able to reproduce the resulting product, so its a no-no for competitions and the like, but if its just for your own consumption, do it, and DO use a blowoff tube.
In fact, my usual rotation of brewdays goes something like: IPA (rack to secondary, dump IPA cake), Session beer (goes down same day I rack the IPA, on new yeast meant primarily for the third style in this chain), Bottle both session and IPA two weeks later, and drop a big beer on the session cake. Speeds up the rotation by at least a week, keeps the pipeline full and varied.