Thanks to Google I might have answered my own question to an extent. Tell me what you think of these choices:

Lamium "Beacon Silver"

Lamium 'Aureum'

Sweet Woodruff

Campanula Poscharskyana

Creeping Jenny? or does she need full sun?

Thanks, and any other suggestions are welcomed!

Lamium Yellow Arkangel

Ajuga wouldn't be my choice. Creeping Raspberry, Rubus calycinoides probably won't take over the bed but it suffers from brown-out = unattractive.
How about one of the hardy, non-aggressive, variegated ivies with white margins to compliment the white-flowering Crepe and add interest to all that green foliage?

Hedera helix 'no name' growing in the Stumpery.
{{gwi:360781}}

Any lamium should work. I have epimedium that trails over a stone wall in conditions similar to yours. Also creeping golden jenny (sorry - can't think of the Latin name). Geranium Roseanne will cascade over the wall and give you some blooms throughout the summer (not many in my heat).
As for woodruff, I love it. But it doesn't do for me in the height of summer heat. It tries it's best to die out. It revives in the spring, but I can count on it only for spring interest.
Another thing to consider is creeping tiarella. Some are meant to creep rather than bunch. I have one that cascades over my stone wall. Sorry, but I can't remember the cutivar. It should be easy to look up though.