Any plants that live in and out of water? Big, easy to find.

Couple of options for you. First, there are many, many bog plants that will be happy in your pond. Lillies, rushes, cattails, fox tail, to name a few. Search for 'marginal plants' or 'bog plants'. Readily available depends on if you'll order off the net.

To address the depth--there are floating pots, that will allow the plants roots to be submerged but keep the main portion above the water line. Another option is to stack the pots on top of something, essentially making an underwater table to hold them at the correct depth. For some, as the plant grows you can increase the depth of the pot until it rests on the bottom.

I am curently trying to grow Cryptocoryne wendtii "Mi Oya" emersed in a sealed jar.

I placed a small amount of some kind of terrestrial fertilizer (15-10-15 I think) on the bottom, and filled about half of the jar with black earth and sphagnum peat. Then I planted the submersed growth. It melted and got moldy, but a few days after those leaves decomposed, I saw new greenish-red growth. Now, a few weeks later, the plant is flourishing.

I also keep it near a SW-facing window and add new water occasionally, since it likes very humid conditions.

I want to try this with Ludwigia repens, which I have heard is marginal, and perhaps Bacopa caroliniana. L. repens has very striking, deep purple-red emersed leaves.

I am not well-versed in pond plants, but I searched for "pond plants marginal" in google and here are some of the results:

http://www.pondmarket.com/store/category.cfm?Category=26
http://www.aquariumgarden.com/pond_index.php?doc_base=mpgip.php
http://www.webbsonline.com/catalog/plants/
I found this site which may be useful to you: http://www.water-garden-ponds.com/

HTH in some way,

Graeme