hi aquilegia :)
hmm, evergreen jasmine, not sure, i have jasminum officinale and jasminum beesianum but to my recollection both drop their leaves wintertime., although beesianum has berries autumn.
I have an evergreen honeysuckle though, it is lonicera similis var. delavayi, it is flowering at present with pure white flowers, and has a lovely scent. I have it twining through a buddleia. Truly evergreen too, not just keeping some miserable tatty brownish leaves on! (It's in a south facing spot though). Having found the plant label it says it will flourish in any well drained soil, any aspect, height to 16ft, can be restricted by pruning.
I believe there is an evergreen clematis that flowers winter/spring time. although I don't grow this-think its armandii? :)