just a few ideas:
> ... find it most unusual that a piano maker, capable of building such large pianos, to a high degree of precision with the best of materials and deftly perfect workmanship, is not known as a true Austrian Treasure! <
That's a well known phenomenon here in Vienna - unfortunately.
As to information on Emmerich Betsy, you might try the 'Landesarchiv' for more:
- Wiener Stadt- und Landesarchiv, Wiener Rathaus (Vienna Archives, records division)
Meldereferat, Magistratsabteilung 8,
1082 Wien 8.,
Maybe they've still got something on Betsy's pianos