I have Heidi part 4, 5 and 6 on DVD (original german version with artworks on the discs) and are willing to sell them. Please contact me on stefansamsson(a)hotmail.com, if you are interrested. For 50 EUR they will be yours and that's including shipping / P&P.
Facts about the films (from this database)
Heidi 4: M?sleins Bergwelt 1992, Dir. J?rgen Baumann / Gunter Otto
Heidi 5: Heidi und die lustigen Spritzbugen der Berge 1992, Dir. Gunter Otto
Heidi 6: Heidi l?sst sie alle jodeln 1993, Dir. Gunter Otto
Actresses in # 4:
Angelica Bella as Keti Kay, plays Zenzi
Angi Baletti as Anja
Danny Miller possibly the mother in the Venice scene
Deborah Wells as Vivian O'Hara, plays Frau Dehmel
Illona Capriati probably the masked blonde in Venice scene
Judith de Ville probably doing the first blowjob in the Venice scene
Lara Sanchez plays Heidi
Actresses in # 5:
Alice Wonder plays Gerda Rittersporn
Angelica Bella as Keti Kay, plays Zenzi
Angi Baletti
Cjilla March as Ilona Capriati, Ditta or uncredited
Deborah Wells as Vivian O'Hara, plays Frau Dehmel
Lara Sanchez plays Heidi
XNK1123 as Ilona Capriati, Ditta or uncredited
Actresses in # 6:
Angelica Bella as Keti Kay, plays Zenzi
Angi Baletti
Cjilla March as Ilona Capriati, Ditta or uncredited
Deborah Wells as Vivian O'Hara, plays Frau Dehmel
Georgina Lempin
Judith de Ville as Ditta
Lara Sanchez plays Heidi