Boeing procedures is to not change configuration and I belive that is mainly due to the fact that things moving in an airstream produce more drag than stationary things.
If flown properly and the thrust managed you should not exceed any limits however it's not deadly if you do, retracting the high lift devices against the manufacturers recommendation based on a fear of breaking them is ludicrous. Let me ask you this, how long do they take to retract, do you have any hope that they would have fully retracted before the exceedance occurs.
Our procedures require f5 takeoffs and to get the LE devices in would require the selection of flaps up, not sensible considering large speed variations and the time it would take.