Get the second account (refer yourself for a free month of WoW via the Recruit A Friend option). Don't spend the extra $25 just to move an existing 70 to a new account. Put the rogue there. Anything from your bank alts mail to an existing 70 and trade to the rogue while grouped up...

I have 2 70 hunters, NE and Orc. Possibly the fastest for powerleveling. I took my NE priest from 25-50 over a weekend of pretty hardcore questing and a few SM runs for the good clothie gear. The revised XP curves from 20-60 are crazy.

Most of us will say the same thing... Why stop at only 2 accounts

Seriously though, enjoy, and even though most of us here box 3 or more...there are ALWAYS good resources to be found.

Good Luck!