10-12' is pretty darn tiny for most trees, unless you are looking for true dwarfs. The michelia will eventually grow much larger than that and is really a subtropical plant......it will not be happy if you get very cold in winter, which some areas of the Bay area can. A larger growing evergreen shrub may be more what you are looking for if size is a real concern. And shrubby plants tend to establish and grow faster than trees as well. Osmanthus is a nice choice but I would not necessarily restrict my choice to O. fragrans - O. delavayi or x burkwoodii could work equally and are also quite fragrant. Another choice would be the compact form of Arbutus unedo, strawberry tree. Very mild fragrance, if any, but an excellent choice for your area with a lot of year round attraction. Very drought tolerant once established, as well. Pittosporums, choisya and azara also offer fragrant evergreen choices and respond well to pruning to keep size in check.

Uhm, Campsis radicans is another. Fast and aggressive(will literally cover your house because it climbs by rootlets) but beautiful flowers that are hummer magnets.

Interesting photos/tree, and very tropical looking too. For scent, almost everyone loves lilac but when I think of scent I think more of summer blooming plants which I can enjoy on warm summer nights sitting outside. For that I love Flowering Tabacco (nicotiana syvestris) easy to grow from seed though quite huge (3 to 5 feet high). I also love madagascar jasmine (Stephanotis floribunda) which I have as a vine growing on the deck and take indoors as a houseplant for winter. I just realized this year that Petunias also have a nice fragrance, if grown in quantity. This year I bought a gardenia which seems a bit difficult to grow (loses leaves, drops flower buds) the blossoms are very fragrant though I have to say it's nice but not my favorite fragrance (under the heading to each his own).

Gold medal to Kris and silver to Tony :) It was in the Loganiaceae family and I've received a reply to my email from Fairhills saying it was Fagraea berteroana. I wasn't sure if they were right at first as the reply said white fruit but the plant we saw had orangy coloured fruit, but after I had a google I managed to find descriptions that mentioned white fruit and another that said red fruit. Everything else fitted so I assumed it was right. It supposed to have a beautiful perfume. I hope it is as good as it sounds. Does anyone know if the fruit is edible? Here is the description Fairhills sent - Fagraea berteriana An attractive shrub or small tree with large, lanceolate, thick, fleshy, glossy, reddish green leaves, paler beneath. During summer it bears PALE YELLOW, TUBULAR, FRAGRANT FLOWERS, followed by white fruit. Found on stream-banks in the lowland rainforests of N.E.-Qld. Height 4-6m Spread 3m