I was in the market for a plum tree a couple of years ago, and I bought a semi-dwarf tree. It seems happy but hasn't fruited yet.
The other day I found the tag in the dirt and looked it up--it's a semidwarf, hardy variety called "Toka."
Now, I'm pretty sure I wouldn't have bought anything if it didn't say it was self-fruitful (no room for two trees) and the chilling hours were relatively low, but I'm wondering if I'm mistaken. It seems to me that a hardy plum is probably a poor choice for my location.