I've done 100+ extra quests for them. I did 3 special quests for them so far, and I've done about 80 extra quests for them since that one. :\

Forever. It takes forever... and a day.

I just want to make sure I'm not doing something wrong.

You need to do one more special job for one of the cities and then you can become Guild Master. It took me forever when I was playing.

The special missions are unlocked after doing 5 regular jobs in a given city (Whiterun, Solitude, Markath, Windhelm).

Only do missions for the city you lack - you can turn down jobs without consequences, or simply reload.

You could have stopped at 25. Like someone else said, once you've done 5 jobs in a city, you'll get a prompt when you talk to Delvin: "What's this special job?" or something along those lines. Then you go do it and come back to do the next.

But you don't have to do Riften.

It's worth nothing that if you don't do the special job for Markarth BEFORE you complete The Forsworn Conspiracy/No One Escapes Cidhna Mine, the odds of getting a job in Markarth suddenly get driven into the ground. If that's the case here, ask for Bedlam Jobs from Delvin and ask for something from Vex. Just keep turning down jobs until you get ones that send you to Markarth, there's no actual downside to turning down jobs aside from a verbal reprimand from either Vex or Delvin.

A freaking long time.
Even if you ruthlessly pursue the quests for the trophies and do nothing else, which I did, it takes a long time.

Do 5 jobs of your choice in each city, do the special job, become guild master.
Save before getting jobs, then you don't have to turn them down if you don't like them.
You just reload.

You have to do 5 jobs in each of the major cities to get a special job for that city, once you do them all you finish the quest.
If you get missions that you don't need, decline them until you get the ones you do.

I did'nt do the tedious Forsworn quests and I got markarth jobs. All the options were there.
I took bedlam ones because it was easier at the time. And I was a little confused about what you had to do to get the trophy, lol.

But I'm pretty sure I've done at least 10 in each city and I haven't gotten the last special quest. Maybe its glitched?

Oh and I haven't done any at all in Windhelm. They Haven't given me any jobs to do there. :\ Maybe that is why??

That's what I'm saying, that if you wait to do the special job in Markarth until after breaking out with the Forsworn/slaughtering them all, then it becomes really problematic and unlikely to get jobs there for the special job.
Yeah, that's your problem. Wasn't aware of anything potentially jamming up the likelihood of getting quests in Windhelm.