You can get them in any mode, but unless you are doing it in a difficulty that is about equal to your level and equipment, you are being a cheapskate... >_> If you are going to be an "Max Attack Master", then you might as well master it; doing 20000 normal attacks (or less if you have a Shot/Sword etc) doesn't seem like mastering anything. But that is just my opinion.
I actually went to Forest in Hard and got some blue-level regular weapons beforehand to do it. >_>
Edit: I started a VH MA2 run with Zelda... it was actually a little tough... I found a Hildeblue and it dropped a Victor Axe... right after that I was mailed by a lv38 friend of mine who wanted to join... So I restarted and made a Hard game. Two S-Berrill's Arms dropped and we each got one of them. Then I did a solo MA2 in Hard, during which several people mailed me to get in, and I ended up forming a team good enough for Ultimate... But then my parents decided to start taking down ceiling tiles and they didn't want me in the basement because I have a cold and there is "too much dust." -_- I was on the other side of the room... (It's a big room)
Edit2: Wow, no one's posting. >_>
Megaman got to VH today, I played him while I coulndn't be online. (Move the Cube upstairs

) Now lv50. Found a P-Arms Arms while in Hard Caves.
Zelda leveled to 152, now has the Aura Field, I have a (blurry, non-PSO+) picture that I will post tomorrow... I also mastered MA1, and got 2 hearts... I have about 3500 MA2 points.
Samus got another MA1 heart, and nearly had the Fomarl MA1 heart (hard to find a Fomarl who got 10000 points, as you may guess) but then due to the typically reasons, that didn't work out...
Too legit to quit.