You may want to check out the many precast block style retaining wall systems that are now available. Keystone Block systems are one example (of many). They all use stacked interlocking blocks which allow free drainage of the backfill through the wall, thus reducing loading from water pore pressure against the back of the wall (as in a traditional retaining wall). The higher block wall systems utilize geotechnical fabrics and earth backfill to add support to the walls. These walls have a pleasant finished appearance and can readily placed around curves and varied in height. The are becoming very common and you might even find the materials available in places like Home Depot. The companies can provide you will design and engineering manuals, but if you have any unusual soil conditions or serious site conditions, such as closely spaced house, you may want an experienced designer to look at it.