I had not seen this thread. I have been researching into autumn coloring plants for our climate for quite a long time now. This garden has many peculiar microclimates, often a few metres apart, with moist areas (mainly in the low garden, but not only there) and dryish, tipically mediterranan ones (mainly on the hill).
Therefore we grow Gingko biloba and Japanese maples not far from Spathodea, Carobs and Olives.
Having said so, I must add that in years such as this one there is practically no Autumn whatsoever - we are still in a warm spell and most of the garden is in full bloom and in great glory. Forget about autumn colors that in favourable years appeared by the end of November! To have the dramatic color changes, plants need cold nights followed by bright days; we have the latter, but no sign of the former. There were somegood rains though, so real mediterranean plants are actively growing, some are blooming, and they certainly don't contemplate shedding their leaves in this season. Therefore to have a display of colors one must turn to non native plants.
My personal list for foliage colors is the following:
Pistachia chinensis
Rhus typhina
Lagerstroemia indica
Cotinus coggygria
Parthenocissus ssp
Persimmon (Dyospiros kaki)
Koelreuteria bipinnata
Triadica sebifera (syn. Sapium sebiferum)
Nandina domestica
Punica granatum
Plus the above mentioned Maples (Acer) of the palmatum group (grown in half or full shade) and the Gingko. When they feel like performing they are gorgeous: a couple of years ago they changed into an incredible flash of bright oranges, yellows and reds!
A good color should also be provided by Cedrela sinensis (now called Toona sinensis), I read somewhere, but I only planted one last year, and this year I don't hope to see much in terms of color change. We will see in the future.