Sorry, this isn't about the sheet music question. But there's a couple articles about Roma music at The Patrin Web Journal. The articles are in the culture section.

And here's something from the same site, in the 'occupations' section, about the 'secret' music:

"There is another, quite different type of music that is authentically Romani, a highly rhythmic progression of tones in which few or no instruments are used. The dominant sound is often that of clapping hands. This music greatly influenced the flamenco, a dance that originated in Andalusia and which has become famous throughout the world. From Andalusia this style spread across the Iberian Peninsula and then to Spanish America, until flamenco song, dance, and guitar playing became a generally accepted form of popular entertainment. This stirring music and dance, performed by proud men and women stamping their feet and snapping their fingers with awesome intensity and passion, is largely associated with the Gitanos. Nonetheless, as with so much Spanish music, what the Roma did was to adapt and popularize a dramatic and exciting dance form that is traditionally Spanish and not Romani. The same has been demonstrated for Jewish klezmer music, which features unusual scales and lively rhythms."

http://www.geocities.com/Paris/5121/

---Lepus_Rex