Catherine, I have Sempervivum growing in a stone wall and the hardy sedums would look good. Have you checked out Squaw Mountain? They have a large selection of hardy Semps and Sedums.

Hi,
1) take the time to see what others have done to get ideas about shape, plants, what you like or not, etc. This includes searching the internet, visiting nurseries and gardens in your area, going to garden shows, periodicals, etc. Take into account climate (zone, sun, wind, rain) and soil conditions when looking at plants.

2) decide on a theme it can be formal or informal, layout and design a scale plan of the intended area, include focal points, paths, sitting areas, special features, adding or moving rocks, etc. Think about how the garden will look through the different seasons.

When choosing plants take into consideration native plants as part of your landscape. At the same time consider what kind of animals to attract (birds) or not attract (deer food). There are so many wonderful plants to choose from; flowering, perennials, annuals, succulents, alpines, decidous, evergreen, shrubs, dwarfs, bulbs, groundcover, enjoy!
ciao

Here is a link that might be useful: looking for ideas