Relion have just released information and prices for a new Insight range of Lithium batteries that are designed to be drop-in replacements for wet-cell batteries.
They come in 12V, 24V, 36V and 48V sizes and you can parallel up to 128 with no additional hardware. The 48V has a 30Ah capacity so you'd need to parallel 3 or 4 of them in a golf cart.
More information at
relionbattery.com