Graemsay said:I'm currently in California (LA), and it is a wee bit hot.
If you want to stick with leather then kangaroo might be the way to go. It's thinner than cowhide, but has a similar sort of strength. It gets used by a lot of the racers as a consequence.
You could also get the jacket perforated to increase airflow.
This is a picture of a kangaroo suit that's been heavily perforated. It's made by BKS (who are great), but you need to get over to the UK to be measured up for one.
(I recently got a set of BKS's finest, and will post a review when I get back to the UK.)
There was talk of Goodwear Leather making a kangaroo A1 a while back. It might be worth asking them, but you'd need to get all the seams double stitched so that they don't burst in a crash.
If you want to go for a canvas jacket then the Belstaff Mojave might be your best bet. They're still heavy, but include all the armour. And are very, very cool.
Both Draggin' Jeans and Hood Jeans make Kevlar lined denim jackets and jeans. I don't know if Hood ship internationally, but as you're buying direct then you can probably ask them.
Lastly, if you just want plain denim then take a look at Iron Heart Jeans, which are available from Self Edge in SF. I haven't seen them, but they're made out of 24 oz. denim, whereas most really heavy jeans come in at 12 to 14 oz. Apparently they were designed by Japanese bikers.
Edited to add: The Scrambler is very cool.
^ I wore my Iron Hearts yesterday riding...must have been at least 100 degrees out. They were hot, but bearable.