The summary and good news is: most coins should start staking... right about now!
First a correction.
It turns out that coin maturity is indeed measured in 7-days clock time, NOT 5040 blocks as I said before.
Some background info on that: last week, many people reported that their coins were 7 days old, but still not staking. So with the slowly moving blockchain, I assumed that the wallet was looking for (5040) blocks/confirmations instead of one actual week and that in the startup phase, maturing would probably take longer than 1 week. (I tried to get confirmation from the dev on that, but couldn't reach him).
As it turns out, the wallet is definitely looking at a 1 week time period -- in seconds, to be exact, the code says:
Now, you might remember that during startup, the blockchain was stuck for a while between blocks 10124 and 10125. That happened exactly one week ago. This means that all coins that were transferred then, or shortly after that, will start staking about right now!
To check the maturity of your coins, you can still use the Coin Control screen. But it's better to check the 'date' column instead of 'confirmations'. It shows your local time, so just subtract one week. You can also use the transactions page.
For those who still want to know the number of confirmations their coins need: Last week, a lot of blocks were produced: about 6200 instead of the average 5040. That means that at the moment, your coins need about 6200 confirmations to start staking. But again: just look at their transaction date.
Hopefully we will see lots of wallets staking soon! Good profits guys.
In case you wallet is still not staking with 7-day maturity, just let me know. I found some tips in the PIVX community so we should be able to figure it out.
You can see this is indeed the case as the PoS difficulty has increased rapidly in the last few hundred blocks as seen in this graph:
Check it out on Presstab's COLX block explorer: http://www.presstab.pw/phpexplorer/COLX/