Depending on where you live, it may also be possible to grow your own rainbow tree ($100, Fast Growing Trees). They're hardy in Zones 9-11, which includes parts of southern California, Texas, Florida, and Hawaii. Rainbow trees grow best in full sun with consistently moist soil (they can tolerate short periods of drought, but it's best to keep them well-watered). You can also grow the trees in containers in Zones 4-11 if you bring them indoors before the first frost.
In their native environment, rainbow eucalyptus trees can reach over 200 feet tall. However, they'll stay around 100 feet in the U.S. (they won't grow quite as tall outside their native tropical forest habitat). You can keep them even shorter by pruning them regularly. These trees grow fast, and it's not uncommon for them to shoot up by five feet in a single season, so they can reach towering heights in almost no time.
Check restrictions for your local area before planting. Right now, the University of Florida's Assessment of Non-Native Plants advises against planting them because they have the potential to be invasive.
Although pictures of these trees are stunning, they don't quite capture the awe of seeing them in person. A real rainbow eucalyptus can stop you in your tracks, so if you find yourself in an area where the trees grow, be sure to check them out.