[dice]

There are a few to consider that have been developed
outside the US with most of the traits of the dwarf
cultivars that the Dwarf Project has been working with.
Demidov, Siberia, and Russian Red come to mind,
for example.

The first two are usually described as determinates,
but I have had Siberia plants set fruit from mid-summer
until frost. (It produces kind of small, seedy fruit in
modest numbers, so it may not be an auspicious breeding
partner for the Dwarf Project, despite belonging genetically
to the family of rugose-leaved dwarf cultivars.)

Where one might find genealogical documentation for
tree-type dwarf cultivars developed in the former Soviet Union
is anyone's guess, but they may have done more work over
the last century with this type of cultivar than North American
breeders.

Edit:

(Russian Red, developed in New Zealand in the mid-20th century,
was probably well-documented at the time as the product of
an agricultural research project. It would be second nature for
researchers to write everything down. Whether those records
have been preserved as something of value, who knows.)