Hi Tilly, I have had the same Problem, Any of My tropicals that havent survived this year arent gettn replaced.. OK a couple of suggestions, Survivors In my unheated greenhouse. 2 fleeced TF (treefern) Black Bamboo, Oleander nerium standard, Lillie's etc... Outside survivors, Phormium yellow wave, Bogstandard Phormium :) Various Hostas and ferns, Gunnera fleeced in pot is looking promising,I have my fingers crossed for my Rodgersia, but im hopefull :) The Acer is budding now also my Yucka is looking fantastic! Obviousley, Cactus Daliah and Begonia are wrapped up and kept inside, Ground cover, carex is good, and hosta, and lots more i cant think of off the top of my head lol
Verbena Bonariensis (6ft) and crocosmia Lucifer are great for colour also Coleus is a great tropical looking filler, I see you live in a warmer climate than me, So anything that survives up here will certainly survive down there ... Good Luck with your new plans, Pics would be great when you get started...Dee..

Can we assume that it is still frost free?
If so, Tacca chantrieri would make good ground cover and is reputed to take a couple of degrees of frost.
Strelitzia reginea and nicolia (Giant White Bird of Paradise) should be fine in a cool frost free glasshouse.
Sollya heterophylla is an Australian climber which should be hardy down to 2 or 3ºc (link below)

http://www.flickr.com/photos/35724365@N05/4685326657/in/set-72157623278656473/

Plumbago?
Tibouchina urvilliana should flourish

http://www.flickr.com/photos/35724365@N05/5051371091/in/set-72157623970680010/

......as should Clerodendrum ugandense

http://www.flickr.com/photos/35724365@N05/4636231999/in/set-72157623970680010/

Several Dendrobium orchid species need a cold spell to bring to bloom, such as "winter beauty" below

http://www.flickr.com/photos/35724365@N05/5409948673/in/set-72157623291084463/

Another orchid that should thrive as ground cover would be Pleione maybe.

I grow all of the above except S.nicolia.

There should be a great choice of climbers too. I'm currently waiting for Lapageria rosea to germinate - again, fine if it's frost free.
And Passiflora are hard to beat. My favourite is P.quadrangularis (link below), hardy down to 2ºc.

http://www.flickr.com/photos/35724365@N05/5052176210/in/set-72157623971088999/

Hope that this gives you a few ideas.

Mediterranean Fan Palm (Chamaerops humilis), Windmill Palm (Trachycarpus fortunei), Pindo Palm (Butia capitata), Cannas, Aucuba, Southern Magnolia (Magnolia grandiflora), Seville Orange (Citrus aurantium), Gardenia (Gardenia jasminoides), Cast Iron Plant (Aspidistra elatior), Tobira (Pittosporum tobira), Star Jasmine (Trachelospermum jasminoides), and Sago Palm (Cycas revoluta).

All of these can stand temperatures down to -6.5º C, though the Cannas will go dormant and come back from the ground.