You probably won't find a source because most don't come true from seed so people don't bother selling them. You could try buying an ataulfo mango from the supermarket. Those are polyembryotic and at least have a chance of reproducing true from seed. The only problem with those, at least in my experience, is that the less vigorous seedlings which should be the ones that reproduce true usually die off. I have only been able to get a few of them to survive and I probably have tried with about 20 seeds.

If I were you I would just order a few grafted trees. Pine island nursery is a very good source, and I just got an email from Top trop about a sale on their mangoes. Their shipping is really cheap if you order multiple plants and with the sale they are currently having the prices of their mango trees are actually pretty decent as well.

jsvand5, thanks for the reply.. The problem with those nurseries is that trying to contact them by email or by phone is a big headache coz sometimes they never answer (as what happened with me). Actually I'm living outside the United States and I don't know why most of the nurseries are afriad of dealing with international orders?!

In my case, the authorities in our country (the U.A.E.) are very smooth and clear regarding regulations and permits for importing seedlings but even though no one of those nurseries was helpful or cooperative with me, that's why I turned to try buying seeds online (although I know that they're not reliable or feasible).. I think I'm going to become desperate coz the only sources for quality mango cultivars are in the United States.. I don't know what to do!

I don't know if it's any easier to get plants from Australia, but there is a pretty good selection of mangoes over there as well. Might be worth a shot. I know they are very strict about things going into the country, but I am not sure how it works for exporting. Maybe if you can get a large order together you might be able to find a nursery that thinks it's worth the trouble.