It might help to define the word "small" in your request since small plants in one person's opinion might still be 4-6' high and wide while another may be thinking 1-2' tall and wide. Also, the space you have available for planting might be helpful... length and width of the intended planting area perhaps?
Thanks
Steve

Good point Skeeter. I'm thinking of something more along the lines of 1-3' tall, to sit in an area about 3' x 3'. Here is a picture - the new shrubs will take the place of the spindly things sitting by the Yaupon hollys.

I'm a poor choice for recommending ANY shrub to anyone but that's a wonderful area that would benefit from lots of color. A small rose perhaps as a centerpiece? Maybe a variety of small Encore Azaleas (something like 30 varieties available now per Encore's website).
Either should easily tolerate both the heat and the intense afternoon sun, especially if kept well mulched.
JMO
Steve

Another idea just hit me... perhaps a big round pot roughly centered with annuals planted around it. That way, the color could change by season if you wished and the higher (pot) and lower (soil) elevations could be used for either similar or contrasting colors. In summer, you can always fall back on sweet potato vine as a groundcover as I haven't found any climatic conditions other than freezing that will kill it and it loves hot sunny areas... good color but no blooms to worry about in one package. SPV does need watering though so that may take it out of your personal lineup for this spot.
Just throwing out ideas here...
Steve

Thanks for the ideas Skeeter. I've considered going to roses there as my failsafe, and I like your pot idea. I've been trying to find a place to put azaleas as well, but assumed this might be too hot/sunny for them, plus if they need acidic soil I'm guessing this is a tough spot. If anyone has done azaleas around Austin in a place like this I'm all ears. Thanks again.

how about the flowering rosemary. Will smell good if you brush it and no thorns. Drought tolerant too. It looks great in a pot too. I am a big fan of curled leaf parsley in pots with pansies for winter. Summer could be zinnias