I think it can sometimes work. But only with certain combinations, where at least one of the perfumes is very simple, and where the basenotes are complimentary.
Jo Malone scents are wonderful, and they are ideal for layering because they are so simple and basic. Her Grapefruit is without doubt the standard by which any other grapefruit scent can be judged. It's the perfect rendition. Some of the other scents in her range are also very good.
One good combination I've used now and then is to dab on some Miller Harris Terre de Bois EDP, then follow by a fine mist spray of Guerlain Vetiver; a wonderful effect!
Diptyque Tam Dao is another good "mixing" scent, because it is such a pure sandalwood basenote. Could be exciting with some citrus on top.