While I think such a documentary is a great idea, I think this will never happen:

"Ideally the protestors in the film should represent the entire range of the political spectrum (right wing to left wing. gun rights to animal rights. pro-life to pro-choice. etc)."

Ideal is hard to find in the real world. This is a very one-sided battle, and pretty much always has been in the US. The powerful and rich are aligned against the powerless, and have the police, courts, and lawmakers, on their side.

You'd be very hard pressed to find right wing protesters being abused in the same way as environmental protesters (or, at all, for that matter). Because the right wing protesters aren't fighting for anything that oil companies, for example, would find threatening. It takes a combination of vast wealth and state/corporate collusion to get the kind of violence we've seen in the environmental activist community.

I've been amused to note that Alex Jones-sponsored gun rights rallies are vastly less likely to be harassed by cops than anything I would be involved in.

The kind of dissent that is most likely to be quashed is that of the powerless against the very powerful. White guys who support the death penalty don't fall into the category of "powerless" and their opponents are not the powerful (the powerful like having more tools to keep poor people in line and to give teeth to their threats, so are unlikely to worry about someone supporting the death penalty).

Pro-life vs. pro-choice? This one I'm really familiar with. Take Texas as an example...during the recent battle over womens reproductive rights here, the surprisingly peaceful pro-choice side had their heads smashed in (http://www.dallasvoice.com/watch-12-arrested-tx-senate-oks-s...), were aggressively searched , had tampons removed from their purses (http://www.thedailybeast.com/witw/cheats/2013/07/12/texas-co...), were falsely accused of trying to bring feces and urine into chambers (http://www.elpasotimes.com/ci_23960175/el-paso-times), were spied on by DPS officers. No pro-life proponents were arrested, or detained, or harassed, despite the occasional actual assault on pro-choice protesters. All of this, despite the fact that pro-life supporters have literally murdered people in support of their cause...I'm not suggesting that DPS should have been harassing pro-life folks the way they were harassing pro-choice folks; just that it's clear which side the power was aligned on, and to what end.

Most right-wing "dissent" is manufactured outrage over imagined slights (or wealthy white people being pissed off that poor brown people could possibly want to be treated equally). I lean libertarian, some days, and so I'm sympathetic to some "right" causes...but, it's clear that when business and the poor go to war, it is a one-sided battle and nearly all the violence is being initiated by police. If we have to find examples of right wing protesters being abused in the ways that those on the left are being abused, we'll never see anything resembling the documentary you've imagined.

Anyway, I went looking to see if such a documentary existed, since I'd like to show such a thing at one of the Revolution in the Park movie nights I host in Austin. Couldn't find anything exactly along those lines, though it looks like someone was planning to make one last year, but seems to have stopped updating: http://examplesprotestdoc.wordpress.com/

But, most documentaries about protest cover the outsized response of police, because that's always a big part of the story. Of recent films, We Are Legion, 99%: The Occupy Walls Street Collaborative Film, Blockadia Rising (which is about an earlier stage of the Keystone XL fight, and includes some of the folks I know who've been charged with felonies), all cover how government responds to peaceful dissent.