Hedychium gingers would work for you but would go dormant in the winter.

I live in Fort Worth and I too like the tropical look in my yard.To achive this effect I have added the following:

Sago palms
Cannas
Hardy Hibscus
Mexiacn Fan palms
Bananna trees
Umbrella grass
Butterfly ginger

Hope this helps you out some

Rigo

I'm in NC but also zone 8. Some things I have grown are canna, calla, fan palm, many hardy hibiscus, hedychium (ginger lily), lantana, banana trees, pineapple lily, Pindo palm, bamboo (in containers except the clumping kinds), crinum, rain lilies, all kinds of grasses. All except the palms die down for winter. You'd need a good irrigation system too except for the lantana.