Yes, it can be done.
Can it be done by you, and legally, that is a different story.
Even if you can find a guide, you are looking at a solid 25+ hours to do, if you are good. If you aren't good at Google and/or no guide, or fail to follow it precisely... Odds are all you will do is ruin a Nexus and possibly even lose your account. As mentioned you WILL be pulling your hair out, and MMS is always a fight every time you change roms... IF it works.
Bottom line is this, yeah you can do it, but you could get in trouble (legally), waste a lot of money, pull your hair out, and if you actually manage to do it, you will be stuck with a phone that will either not have mms or could be unstable and cannot be sold. Depending on the phone, you could also end up in jail over it.
This isn't like 2 years ago when there was little competition and the only decent phone VM had was the OV. You have some pretty decent choices now between carriers and phones, and that was the only reason to even bother tacking such a project. Save yourself the hassle and sell your phone, and either switch carriers or buy a One V or Evo V and be happy with your cheap bill. Both phones are awesome and the Evo V is even comparable to the Nexus.