I misread your post.
I think RB/WR/WR/WR is a fantastic move. I've played a few 1RB/3WR/Flex leagues, and the teams with 4 good WRs win more than the teams with 2 good RBs.
the 5/6 turn would be great for picking up a pair of RBs like a Rhodes/Foster or something.
You only need to hit one of three mid-round RB picks to have a stud team. And there is tremendous value in the 6th for RBs this year.
Here's a mock where I drafted from the choo-choo
QB
Carr, David HOU --- 5 0
Favre, Brett GBP --- 6 0
RB
Williams, Carnell TBB --- 4 0
Williams, DeAngelo CAR --- 9 0
White, LenDale TEN --- 7 0
Martin, Curtis NYJ --- 9 0
WR
Burress, Plaxico NYG --- 4 0
Bennett, Drew TEN --- 7 0
Driver, Donald GBP --- 6 0
Kennison, Eddie KCC --- 3 0
Edwards, Braylon CLE --- 6 0
Smith, Steve CAR --- 9 0
Bryant, Antonio SFO --- 7 0
TE
Gonzalez, Tony KCC --- 3 0
K
Tynes, Lawrence KCC --- 3 0
DT
Seahawks - DT SEA --- 5 0
The best part of these type of leagues is you can afford to gamble on guys who won't start the season, but will see heavy action later.