Wha...
Here is a fact...
I have NEVER EVER had a revolution within land that I have always owned.
Ever.
If I notice that some people are getting angry, then I change my civics to one which has more stability (note that the period immediately after the civic change has increased unstability, but after 10 turns on normal speed, and 20 turns on epic speed, it has normally entirely disappeared)
My question is... what are you doing wrong!? As I have said, I have NEVER had a revolution within lands I have always owned, and have almost never had a revolt status of Warning or higher, for those cities.
Once you hit Danger, however, it becomes infinitly more difficult to control that region, so try and nip the revolution in the bud, and take drastic steps to remove the revolution at warning or lower.
That said, with the initial civics, and a 30~40% tax rate, and a happy, connected empire with a garrison everywhere, and either no state religion, or the same state religion, you should be flat AT THE VERY LEAST, in terms of stability!! And once you get better civics, you can be more... mean with your citizenry
[Edit]Note that, unlike Rhyes and Fall, which I don't like, Revolutions mod
tells you what you are doing wrong, so fix the problems which say "Negative", and try and emphasise the things which say "positive"
So, try a revolutions game, and post a save if you get stuck, and we will tell you what you are doing wrong...[/Edit]
Finally, IMO, I find it DIFFICULT to be able to make my original lands revolt, even if I try, in the late game, without HURTING my empire!! So, if you have any major problems, please post a save!!
Because it's broken.

No, really, I can't explain it better than that. And what part of damned to hell don't you understand. I'm never playing it again. And I'll do my best to get my point across.
I had a city rebel, and it spawned 17 units. or 16. That's broken.
Yes it's been awhile since I played, Storm, but it's micromanagement hell at it's finest. It's hell on Earth for all the wrong reasons. It's just wrong, wrong, and wrong!
I don't understand how anyone could enjoy such flawed design with over 9000! issues.
I exaggerate, but still.
I hate Revolutions with a passion unseen by most. I will always hate it.
Hate is a strong word, but it also is the only word that works for me.
Revolutions is buggy, or broken, or useless, or insanely difficult, you pick, it just is one of those, nothing more, nothing less.
Honestly, no one should have to play it unless they want to enjoy hardcore hard mods that make Contra look easy, and make Serious Sam boss fights look easy.

I'm glad it's optional, I really am. I'm just tired of over 9000! people enjoying the bugged/broken mess that does make Master of Orion 3 look like an amazing feat!
Sorry, just the truth.
For this, I think there could never ever be such a city in real life
Um, All cities in the USA. I win.

No, really, every major city in the United States, Possibly even Canada and England all have more than 6 religions in a city. I can pretty much prove it.
Also, Salt Lake City probably has 5 or 6 different religions.
Let me go look up top religions in the USA.
Here's the list.
Christianity 151,225,000 159,030,000 224,437,959 76.5% +5%
Nonreligious/Secular 13,116,000 27,539,000 38,865,604 13.2% +110%
Judaism 3,137,000 2,831,000 3,995,371 1.3% -10%
Islam 527,000 1,104,000 1,558,068 0.5% +109%
Buddhism 401,000 1,082,000 1,527,019 0.5% +170%
Agnostic 1,186,000 991,000 1,398,592 0.5% -16%
Atheist 902,000 1,272,986 0.4%
Hinduism 227,000 766,000 1,081,051 0.4% +237%
Unitarian Universalist 502,000 629,000 887,703 0.3% +25%
Wiccan/Pagan/Druid 307,000 433,267 0.1%
Spiritualist 116,000 163,710 0.05%
Native American Religion 47,000 103,000 145,363 0.05% +119%
Baha'i 28,000 84,000 118,549 0.04% +200%
New Age 20,000 68,000 95,968 0.03% +240%
Sikhism 13,000 57,000 80,444 0.03% +338%
Scientology 45,000 55,000 77,621 0.02% +22%
Humanist 29,000 49,000 69,153 0.02% +69%
Deity (Deist) 6,000 49,000 69,153 0.02% +717%
There are more. With the exception of the last couple on the list, you'll find one in every city.