I was going to use those patterned cinder blocks that you allow grass or ground cover to grow up through because my folks had tons of them they used for bookshelves. That would allow for exactly what you were talking about because we have virtually no curbside parking in our cul-de-sac. My mother died in December and since I had already planted the strip, my wife vetoed me digging it up to place them. I know where you can get a bunch free if that's of any interest :-) It sounds somewhat like what I had intended, my strip was about the same size including the raised bed, here's a pic....

Here is a link that might be useful: {{gwi:22101}}

If you were to use the pavers as tire guides, I'd consider something like creeping thyme before the others you mention. A lower growing, ground hugging GC would seem to work better for this application than something that will get taller - i.e., the helianthemums or genista. The rubus could work, but it does tend to sprawl rather easily and could cover the guides rather rapidly.

And I'd avoid doing this without the paved guides. Even very occasional parking on any of these GC's will damage the plants significantly. It may not kill them outright, but they will get crushed and broken and look pretty unsightly. This would be far less noticeable with the lower growing thymes or similar type plants.

Thanks so much for the suggestions so far. The pavers sound intriguing. Does thyme choke out weeds? Is it fairly drought tolerant? We don't have a sprinkler system and I never seem to remember to drag the hoses to that side of the yard.
Thanks so much!

There are lots of kinds of low thymes, which is what I immediately thought of too. My understanding is that thymes are quite drought-tolerant, though they also seem to do fine in my regular garden beds. Mine are not particularly good at choking out weeds, on the other hand weeding them is a pleasure to the nose.

I'd get a variety, lemon, spicy orange, wooly, mother-of-thyme, maybe throw in a chamomile for a slightly different look. It could be pretty and fragrant.