lorax

Here's the view of someone in the tropics.

In the case of Norway: Zingibers (gingers), Loquat, Yucca, cold-hardy Fuchsias like F. boliviana, Crotons, and aroids like Xanthosoma, Monstera, Anthurium and some of the Alocasias. You can probably also pull off the hardier Hibiscus, like Rose of Sharon. Cool-zone orchids like Maxillaria and Epidendrum can be placed in niches on the pstem as long as your humidity is fairly high or if you're committed to misting daily. If you want a showy backdrop, check out Pampas grasses. I've heard of people having luck with Mountain Papaya, the cold-hardy relative to "standard" papayas, as far north as Oslo. You can also go with ferns, but they're not normally found in the same areas as nanners down here, and unless you use your native varieties they will seriously suffer in the wintertime.

In the case of Ms.Kitty: in addition to the ones above you can probably go as far as Coffee, Mountain Papaya (look in Wikipedia under Vasconcella), Heliconiums, terrestrial Bromeliads, Hibiscus rosa-sinensis, and if you're willing to care for them a bit you can train orchids to go up the pstem when the nannas get bigger - check out the Vanillas for this, since they're pretty low-maintenance. This has the added advantage that once the nannas have fruited you don't have to do more than cut the pstem above the orchids (rather than machete or saw the whole shebang out), since it becomes the support for the flowers. You can also go with Agaves for low contrast, and they're xeriscape plants so you barely need to care for them at all. If the nanners aren't too tall and you're looking for lower-growing stuff, the non-arboreal aroids (Alocasia, Anthurium, and Xanthosoma) are a great alternative, and they've got super-showy leaves.

My fave source for the orchids is Ecuagenera, but I'm biased because I live here and grow Ecuadoran orchids.... The rest of this should be obtainable from garden centers or mail ordered.

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I speak for the trees.