On the 737 the bleedfrom the engines can be selected off for takeoff and is quite routine, in this instance the apu will provide the necassary bleed air for the one pack. Takeoff with the packs off is quite unusual as their will be something of a noticeable pressure change upon introduction of bleed air and pressurisation. So in answer to your query, Takeoff with packs off is unusual, however takeoff with bleeds off is quite routine.