That's possible but extremely rare, so rare I never encountered 30K B24s - Players intending to fly at extremely high altitudes usually take a B17 instead.
Reason: A 50% Fuel B-24 with 8k of bombs takes about 50 minutes to reach 30k, but will be almost out of fuel by then. If you take 100% of fuel, it takes you 90 minutes to get to 30k. The climb rate is almost 0 by then. Actually, it takes 30 minutes just to get from 27.6 to 30k! Less than 80 ft/min rate of climb past official service ceiling.
(numbers on the graph are flight time in minutes)