You might consider a Dart's Gold Ninebark. The yellow/chartreuse color would provide great contrast to the greener surroundings. The peeling bark would add winter interest and the white spring flowers are abundant. It is more rounded than oval. I have one growing under an aspen clump and the partial shade seems to push it out horizontally. It is also next to a Korean Spice Virburnum which adds some height much like in your picture.

Another cornus you might wish to look at is c.alba 'Bud's Yellow'. Light cream - almost white - and green foliage on strong vigorous yellow stems and the stems are pretty showy in the winter. The shrubby cornus might be a problem though if your site gets dry in the summer - that Physocarpus Dart's Gold might be a better choice.

Marshall

I like the Dart's Gold suggestion...technically has 4 season interst.

Although its listed to be a rounded shrub, my experience with ninebarks (diablo and summerwine) proves otherwise. Very upright and oval in shape...but sounds like your guys experience with the shape is consistent with size listings on the web.

Do you happen to get any fall color?

The site is actually very dry...on the back side is an easement...decent slope.

Rose of Sharon hedges do well in full or partial sun.

I'm thinking that was for another post?

How about callicarpa (purple beautyberry)? Mine has a wonderful open habit, it will spread-I have new ones all over the place near the two original ones I planted. The flowers are inconsequential, but the berries in the fall are spectacular, although the robins will eat all they can get.