Custom URL eligibility?

[Cyntheon]

Is there any other way to get a custom URL before hitting 100 subscribers? I feel like I'd be able to promote my account more and therefore get more subscribers with a custom URL, but before I can do that I have to struggle to get my first 100 subs? This seems like a very strange eligibility requirement to me.
Also, does anybody know when and why they implemented this rule? I have seen a lot of accounts with custom URLs with fewer than 100 subscribers, so did they create their account before 100 subscribers were required for this function?
I used to have an account years ago, and remember it being tailored to my username from the first second. I'm very excited to be back on YT, but this is very frustrating to me. The only reason I can think of is that they're still trying to shove Google+ down our throats and want you to create your YT account under your G+ name.

 

[ChrisLegend]

YouTube rules have changed a lot over time and yeah the reason why some accounts with less than 100 subs was able to get a custom URL was because they did it before the rule was introduced. I think this rule may have been introduced so people can't make new accounts and reserve some popular names and then sell it later on to people that want it. Similar to how people sometimes sell license plate names.

I believe at one time it was at 1000 subs and then 500 subs as well but my memory may have failed me here haha. Unfortunately we just have to do the best we can until we hit 100 then we can go custom-style

 

[M1ss T3riosa]

There are two main reasons why some people can get a custom URL before hitting 100 subs. One of them was already mentioned above, the other one is if people associate a website they own with their YouTube account. For example, if someone owns a website called "example.com" and associates it with his/her YouTube account, YouTube will let the person get "YouTube.com/channel/example" right away, without the need to hit 100 subs.