Sounds like it is getting plenty of afternoon sun so you need a sun-tolerant shrub. Rhododendron would not like getting established in such a place, I agree. A dwarf Fothergilla (Fothergilla gardenii 'Mt. Airy') would be appropriate.

Here is a link that might be useful: Pictures

How about Pocomoke crapemyrtle? It is a nice midsummer bloomer, needs sun, and mine is about 4 ft x 4 ft. I've had it now for about 6 years, and even though the article below says zone 7-10, it has not died (knock on wood!) It is not fragrant, but it creates a nice rounded look like in the pictures on the link.

I just read where crapemyrtles are invasive in the south so you may want to check that out, but I've not had that problem here.

Picture:
http://www.onlineplantguide.com/PlantDetails.aspx?Plant_id=1418

Vickie