I get asked this one a lot, actually. Having people alter their stats or have it transferred from one account to another is a pretty common request.
And it is possible, but it is far more difficult than people realize. The way our system saves and stores account information is purposely difficult so that accurate stats are displayed without the risk of having an outside party (e.g. a player desperate for good stats) being able to compromise it. Furthermore, no Moderators, Sr. Moderators, or Admins would be able to do it, as only the Developers who are physically present at our server boxes could begin the process. It is a lot of hassle for what amounts to little reward, but that's how our system works for good reason.
That doesn't even mention the potential abuse. MCSG draws some naturally competitive people, and I know that those said people will be looking for ways to make themselves appear their sharpest; the OP here outright admits that the reason they came up with the idea is to wipe away their records so that they can appear better to a clan. I've seen it happen quite often in other competitive games like CS:S, SC2, TF2, TFC (back when it was considered competitive), and seemingly every version of CoD. Whether they leave the server before their team loses a round, quit every time they die (so it doesn't register against them), or flagging the other team as hackers so the defeat is nullified, people will exploit flexibilities in the system to maintain that perfect W/L or K/D ratio that shows that they're so 1337. It's the photoshop airbrushing of someone's personal statistics: it looks really good, but it's based on deception.
This wouldn't be a problem if it wouldn't require so much developer effort and attention (which are better focused elsewhere), and if it didn't naturally bring about a function which would naturally encourage stat-inflating, unsportsmanlike conduct, and unrepresentative data for competitive-appearance purposes. For those reasons, I don't think stat-changing will be possible anytime soon. If you're unhappy with your current stats, they are a good motivator to go out there and win some more.