The Book Palace has three Modesty Blaise originals by John Burns for sale. The first two are unused art that was produced for Dead Man's Handle and The Xanadu Talisman (both 13x17 oil on card):
...and the third is the original art produced for the Titan Books reprint of the Modesty Blaise story 'Warlords of Phoenix'.
You can view (or buy!) these on The Book Palace website.