Hi,
I've had really good luck with the pawpaw. I'm in Kentucky and they are found in almost every hollow on our 150 acres. We get fruit from them almost every year (of course, as I write this, not this year due to the late hard below-zero spell in April that knocked the flowers/young fruit off).
I've planted seed from the wild trees closer in to the house for easier gathering, and they actually are very easy to sprout if you are patient. Collect them up from any fruit you eat. Rinse 'em, dry 'em, and then put them in peat moss or sphagnum moss in the fridge over the winter. In the spring, plant them directly where you want them to grow. It will sprout in mid-summer here. They also sprout easily and more quickly in pots - probably because the soil in the black pot warms up faster - but they are hard to transplant. If you nick that taproot or don't get it situated right, that seedling isn't going to do well.
I've also traded for some named cultivars from some nurseries. Nursery plants are expensive, but generally higher quality fruits.
One resource you may not know about is the Kentucky Dept of Forestry. They have a wide selection of seedling trees that are quite cheap, especially if you order in quantity. I've had good experience with their seedlings - especially the pawpaws. I think they are seedlings from the Kentucky State pawpaw improvement program.
Here's the link to the seedling order form:
http://forestry.ky.gov/statenurseriesandtreeseedlings/Documents/Seedling%20Order%20Form.pdf
They also have other trees of interest to permaculturists - locusts, nut trees, KY coffee trees, hazels, alder, tupelo/black gum, persimmon, mulberry, etc.
Pollination for the trees near the house has been spotty. I know they are supposed to be fly-pollinated, but the ones in the woods seem to have a high pollination rate without any help so there may be some woodland insect doing the job that isn't around the house area that is more cleared. For those trees, the pollination rate improved dramatically after I hung some small bits of meat in the trees when they had flowers on them. Not the best smell, but that week or three is long forgotten once the pawpaw harvest comes in.
Now if I can just find a way to store them all or get them to a market in presentable condition...
All the best,
Geoff