(d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed.
How about an MD-80? 747?
You do not have to put flaps out to follow the rule as indicated above. A heavy 737 can't slow to 200 and keep the flaps up, so you don't have to when flying under Class B. Just fly the minimum clean speed. An MD-80 taking off heavy will need about 260 knots clean maneuver speed. Only a dolt would leave the flaps out to comply with the 250 rule in that case.
Where do you get your numbers?
MD80 series (reference the -83 here) If you look at the charts, assuming MGTOW of 149,500#, using the 150,000# chart, 33 degress C at sea level, Altimeter 30.06, dry runway, no wind, Flaps 15
Here are your speeds:
V1: 143
VR: 147
V2: 154
Flap Retract: 169
Slat Retract: 202
Final Segment: 223
Clean Maneuver: 252
The airplane will fly just fine cleaned up at 250 and climb no problem. Once you hit 10k push the nose over for a 300-320kt climb.
I don't think the Maddog is like a true heavy that has to have the slats out up till around 280. Comming out of Charlotte, ATC has to cancel a 280 speed restriction.
As for the 250/10k rule, well... Been into North Dakota airports and had controllers tell us no speed restriction below 10,000, and this was on the descent. Ultimately, if this question went to court, I would think the PIC is required to adhere to FAR/AIM regardless of what ATC tells you. Just MHO.