Calamondin or kumquat most likely.

I have 2 citrus seedlings one is about a foot tall, and the other is about 6 or 7 inches. Perhaps you can make them into a bonsai? The tall one is a grapefruit, the shorter is a valencia orange. If you are interested, please post or email and tell me what you are willing to trade. Thank you!

Jayz

Go with the Calamondin, the fruit is about quarter size and round. The kumquat is the same size, but is oblong. The Calamondin will flower and have fruit all year long, except in the winter. They grow good indoor, even up north, as long as they get alot of light.
I would say away from the grapefruit or full size citrus. Odds are you wont get any fruit.

My father has a blood orange tree as a bonsai. It's about 2.5 to 3 feet tall and has one big blood orange on it. Blossoms and everything else though.

I'm going to be growing a loquat tree. I saw a couple of comments about calamondin and komquats...any hints for a loquat?