I have mentioned this in a few other places, but I will mention it here too. I have an Emerald version, and then I got a Ruby version from selling a few Yugioh cards. Anyway, what I did was start a new Ruby game, progress to where I could make a SB, trade Pokes (i.e. 6 Raichu) from Emerald to Ruby, mix records, and voila!, I now have a SB under that Ruby game name (i.e. Ness) with 6 Raichu that I can battle once a day. Then, I reset that Ruby game, start a new game under a new name, progress again, pick a different SB location, and repeat. When all is said and done, I have 6 EV bases, one EXP bases, and my own base. I will even have a SB for my son once he progresses.
Now, I just got the Sapphire version from another trade, and I am going to try to add 6 more bases full of Pokes of each type (there are more than 42 bases in the Hoenn Region), and now I will be able to do my EV training in ONE day!