I don't really have anything I need on your list or vice versa, but I also have an interest in landraces. I have been chatting and trading with Joseph (and it turns out his father too) online for years. I have his moschata landrace and have been making it my own and selecting out what I want. I also grow his gourd mix. I have been starting my own melon and watermelon landraces, sweet pepper and late bolting lettuce landraces.

Here is a link that might be useful: Homegrown Goodness forum

I have some corn that is also likely crossed (grew 3 types in a tiny sq inch garden with numerous other things too). my kept seeds are all jumbled into one bag.

the three main types I grew were:
>Stowell's Sweet Corn Heirloom
>Hooker's Sweet Corn Heirloom
>True Platinum Sweet Corn
I still have some of the original commercial seeds (Seeds of Change) too, but they are older by many years.

pm me if interested in some sort of trade.