A very good, and basic, example of romantic interaction can be seen in the clip below. This is an excerpt from Mozart's La Clemenza di Tito. Here, Annio has just told Servilia that they cannot be together anymore because she is to marry the Emperor. This is a prime example of young lovers (which is a common occurrence with pants roles). There is an extra challenge here because Annio is shorter than Servilia in this particular production. However, this is overcome rather easily and the resulting performance is something beautiful. You can find the link to purchase the entire Zurich Opera DVD here. Vesselina Kasarova, who plays Sesto in this production, is also a great resource for general movement.
The following is a clip from the same production. Here, Annio makes a small (and common) mistake that causes a brief moment of awkwardness. However, he recovers nicely and the scene continues well. The clip is without sound so you can focus on the movements of the singers.
Here is a clip from Der Rosenkavalier with Brigitte Fassbaender and Lucia Popp. Pay close attention to where Fassbaender places her hands and how she holds Popp. The trickiest thing about romantic interactions when playing a pants role is that you are playing opposite another woman. You must emphasize the masculinity even more because the audience is seeing another female onstage to which they can compare you. The entire production is most definitely worth watching, since Fassbaender is such a great performer to learn from for all the little intricacies of pants role movement. (Also, you can hear expert advice on the particular difficulties of this role at the end of the OperaNow! review of this site. That file can be downloaded from my Home Page.)
Another famous romantic pants role is Romeo in Bellini's I Capuleti e i Montecchi. Below is a clip from the Paris 2008 Dress Rehearsal with Anna Netrebko and Joyce Didonato. The dress rehearsal in its entirety can be watched here. Romeo is such an iconic romantic lead and there is much to learned from Didonato's approach to the character. Also, there is a lot of interaction, especially romantic interaction, between Romeo and Juliet so there is a vast amount of material to learn from in this recording alone.
Here is another Strauss clip: this is Susan Graham and Natalie Dessay in Salzburg's Ariadne auf Naxos. As I've said before, Susan Graham is a no-brainer when it comes to studying the pants role movements. Her romantic interactions in these roles are always convincing and natural. There is another clip from this production in the Basic Movement section.
Here, we see Cinderella and Prince Charming from Massenet's Cendrillon. Alice Coote, the mezzo playing Prince Charming, is the protege of Brigitte Fassbaender and you can see the attention to physical and vocal detail in terms of bringing across the pants role. I think she's especially convincing, especially when paired with Joyce Didonato, a mezzo who is no stranger to pants roles.
More coming soon!