Well first I would suggest calming down
and not reverting to hardware issues just yet, Bootloops are pretty common, especially when using phones which were meant for the (a bit) more advanced user, it's advantage is also it's flaw, being a modding monster that it is..
And this is by no means a flame - but I wouldn't want my wife to have a GN for that exact same reason, yes - she knows about flashing roms and stuff, but she needs a reliable phone, that will work and do what she needs it to do and nothing more, as opposed to me, I like to mess around a bit with my phones (also not that much, I plan to stay stock with my GN).
To your question, I don't have any experience with RMA's but it maybe worth a try.
You also mentioned she fancies the one-x.. that means she wasn't really keen on buying the GN in the first place (I believe).. and also - and don't take this the wrong way - I think she\you don't really know what the GN is all about, this isn't a phone for everybody, I mean - it is, but it's a shame to see it fall into hands that do not appreciate it for what it is, think of it as a nice new Ferrari, sure - it'll get your wife to work But she is not going to the Nurborgring to time her laps with it.. she'll complain that once in a while the clutch is too sensitive and that she cannot count on the car to take her to work every day, and that she really fancies the new Volkswagen beetle... you get my drift
Also - I believe that flashing to the 4.0.4 will sort the bootloops, which usually has everything to do with the kenrel.
Best of luck!
p.s. All of the above is said in a humoristic way!