Go to the EXCHANGES section of this forum. Since you already have some banana trees, you can probably swap pieces of what you have for other varieties for the cost of postage. You might also fill out your trade list. People like to know what you have to swap for their bananas.

Try "Going Bananas". They're right there in Homestead, FL, so you can just pick them up. They have all of those plants that you're looking for. You can Google them or look them up in your phone book. If you go to their website, they list all of the banana plants that they carry and their prices.

Wellspring Gardens is another. This company lists banana plants in eBay.

Another one is "greenhousebusiness.com". You can just add the url prefixes on this one.

Chong