Lipos can be used just fine w/ brushed motors, they are just batteries.
There are other things that create runtime though too.
What type of motor?
What type of surface?
What kind of gearing?
What are you looking for from your electric vehicle?
GEARING plays a huge part in Run time, but the lower the gearing, the slower the speeds..but the longer the run time.
Too often people want SPEED and give up run time...(and can't actually achieve the SPEED they are looking for, due to surface conditions, or area size) Then end up over gearing and getting things too hot...and KILL their run time.
If you were to use something like a 5000 mah LIPO, you should have LOTS of run time. With 2 packs you could have quite a bit of run time and fun between charges.
NOTE: Brushless Motors ARE more efficient, and can when geared properly give you even more run time.
(as far as a battery that lasts 30 minutes - there are just TOO many factors involved to say if YOU could get 30 minutes out of ANY battery... things from Gearing, and gear efficiency, speed, surface, style of driving, type of surface...etc.) MOST New style batteryes (MATCHED Sub "C's") are tested at 35 amps, and run for over 400 seconds...if you gear to only use roughly 15-20 amps vs. the 35 amps tested...you'd get over 15 minutes run time. If using a STOCK 27t motor, this can be achieved. If you use a 19t or MODIFIED MOTOR - you will NOT be able t get that kind of run time in most cases.