Passiflora ligularis (Sweet Granadilla) is said to be the sweetest passion fruit, and Passiflora mollissima (Banana Passion Fruit) is also said to be sweet.

Other than incarnata, Passiflora edulis edulis, edulis flavicarpa, quadrangularis, alata, and laurifolia are also very edible.

P. edulis 'Frederick' is said to do really well in S. Ca, but it will get really big. Here is a description.

"Passiflora edulis 'Frederick' is the premier fruit producing passiflora for warmer areas of Southern California and will grow inland with protection. The flowers are fragrant and large. The fruit is as large as a goose egg with a purple skin and delicious pulp when ripe. The fruit should never be picked, it must fall naturally. If it is allowed to wrinkle a bit after collecting, it becomes sweet ambrosia. The plant is very productive in warm areas. This outstanding Patrick Worley hybrid is vigorous and blooms from late spring until fall. This plant is excellent for a sunny location and makes a good, rapidly growing screen for an unsightly fence or outbuilding."

Sounds great, as I have an extremely unslightly fence to cover.