Granprix Attack

2.Nc3 a6!? is a very popular move between Najdorfeers. Simon Williams has made a brief video about it at chess.com here

This is a correspondence game I've played recently:

And another, OTB one:

Of course this medicine also works against the Closed Sicilian. I like it, this is a good way to avoid quite a few stereotyped "solid" variations without excessive risk.

Possibly helpful:

Experts on the Anti-Sicilian by Jacob Aagaard & John Shaw (ed.) (2011)

https://web.archive.org/web/20140626195254/http://www.chesscafe.com/text/hansen147.pdf

Fighting the Anti-Sicilians by Richard Palliser (2007)

https://web.archive.org/web/20140627130915/http://www.chesscafe.com/text/hansen106.pdf

Anti-Sicilians: A Guide for Black by Dorian Rogozenko (2003)

https://web.archive.org/web/20140627050549/http://www.chesscafe.com/text/hansen50.pdf

Sveshnikov vs. the Anti-Sicilians by GM Evgeny Sveshnikov (2014)

Starting Out: Sicilian Grand Prix Attack by Gawain Jones (2008)

https://web.archive.org/web/20140627012235/http://www.chesscafe.com/text/hansen111.pdf

Coming soon:

Grandmaster Repertoire: Beating the Anti-Sicilians by Vassilios Kotronias

FYI:

David Rumens was (most probably) reading the Soviet chess magazines (Shakhmatny Byulletin and 64): The famous Russian study composer IM Genrikh Kasparian was employing the Grand Prix in his modern form since the mid-fourties...

Actually every serious chessplayer in Europe was reading these magazines: They were full of great material, and dirt cheap.