Yep. I would go with thunderskies or similar prismatic packs of lifepo4. 4 cells per 12v, and monitor with a voltmeter on each cell.
Cost effective? Maybe not, far as I know the golf courses have not adopted them yet in my locale. Definitely the way to go though, if you need more range than possible with the lead. I'd stick with the lead if you are able to charge at frequent intervals after short runs.
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE
Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum
See battery technology section, FAQ thread at the top of the page for lipo noob info.