It looks like they make a very pretty bonsai, though fruiting may be a little hard to tell. Do you know what the criteria for fruiting is?

I remember reading that while citrus makes a great plant for it, you can't expect fruit if you're growing it indoors and are not using grow lights as it is kinda needy.

The leaves look a little too big for bonsai....

The only papaya plant I've seen grown had very large leaves, as Ryan mentions.
Plus, the plant was more than seven feet tall, with a single straight trunk.

Josh

Hey all,
Thanks for the input. They are very straight, tall specimens. I didn't consider the size of the leaves. That is pretty important. Any thoughts on Rainbow Eucalyptus?

Here is a link that might be useful: Envi Sci and Fishy Plants