Main consensus here is that you will get back to your Qwerty speed in three months (~90 days) but with more comfort.

If you type fast in Qwerty you will type at least with the same speed in Colemak. The fastest speed depends only on your individual muscle strength, finger lengths, nervous speed etc.

For fastest speed, check hi-games.net with plenty of 100+wpm Colemak typists there.

Good luck.

If it took you a month with Dvorak, then it will take you a month with Colemak with the same time each day for practising.

The stories is various about the converting length. It depends on each individual, but it is the same for different layouts.

Max speed doesn't depend on layout. If all computers users used Colemak, then the top record would be ~220wpm with Sean Wrona on top, as usual.

Qwerty is on top now because it has massive fan base.

Comfort is the trademark for all alternative layouts. It is just that Dvorak and Colemak bring comfort in different ways. 

For typing speed, most Colemak users' speed is faster than their old Qwerty speed, but not much. Even Sean Wrona would type in Colemak a bit faster if he could practise at least 10 years, just as he has done everyday with Qwerty.

Mostly typing tests are only 2 minutes or less, so you can type fast then rest. For such short time burst, layout does not matter. Qwerty users would be more tired while doing so, but all we care is the top records.

For longer time, Colemak/Dvorak would win over Qwerty because of the comfort. That feeling of comfort is not recorded, however. Only felt.

Hard to say. I don't think that Sean Wrona would necessarily do much better with Colemak. His technique transcends normal touch typing as is the case with most of the fastest typists, so he'd have to relearn a lot of words in the new layout rather than just the letters. And that's a big undertaking. Similarly, I don't think it's possible to speculate what Barbara Blackburn would've gotten out of today's typing possibilities. At these performance levels it becomes very individual and I don't think that even QWERTY is all bad once you optimize your technique for it. Well, given the number of very fast QWERTY typists that's actually proven.

Colemak is about less movement, and more comfort and rolls. Dvorak about the same, but more relearning and hand alteration preferred to rolls. Both are primarily more comfortable, and likely (but not quite proven!) to be potentially faster than QWERTY. It's also pleasing to write on a layout that's properly thought out! :)

I mean, a hundred is good, but it doesn't take much time to reach it, given regular practice. I can say that almost every day since I've started, I've practiced for a while, many days over an hour just touch typing for speed, if not word processing and other practice. It took me about three months, and I reached almost 1.5x that speed in about half a year more, so I find it unimpressive, in the manner that Sean Wrona would find my abilities rather unimpressive given his much superior level.

Honestly, speed typing to me is being able to compose the words and have them drawn up from memory as fast as possible. Most of that is due to muscle memory, but some of it could possibly be just brainpower.

>The idea that you can reach your Qwerty speeds in a new layout in a few months sounds pretty incredible to me.

It's all in the practice. I would practice for over two hours almost daily when I started learning Dvorak, and that let me grow. Now I have to practice less because of overpractice and carpal tunnel (given that most probably take longer to reach 140+), so I can take more time to refine every aspect of time-saving.

Informative, very informative. Thanks for that.
But I'd say 50 wpm is a bit low. I think that when I'm typing out forum posts, I'm generally typing a pretty constant 80-100wpm, unless I really need to think of what I'm saying, like when I'm writing stories or poetry.
These days it seems like quick typing is very useful, and gamers sometimes need to type out messages quickly (say in LoL), so I'd say that for general use, 50 wpm is about all you need, but for more keyboard-active, I would put the bar more at 80.
Hopefully I'll reach that final phase sometime!