Last year my burning man project was to help "The Artery" light up art installations that were not safely lit.
I ended up buying a load of simple and cheap solar powered patio lights as well as a bunch of bicycle red flashing tail lights.
These lights can be modified easily to give them some extra juice . Typically they will not last all night because they use the cheapest possible rechargable battery. The "hack" is as simple as simply changing the rechargeable battery to a high "amp hour battery. What I did was use NIMH 2600 mAh batteries (from all-batteries.com) I opened up the lights , swapped the battery, and i was done. Now my lights lasted all night!
If you want accent lighting, then I suggest that you go LED . there are a number of ways to do it. you can roll your own, with LED's from ebay, or you can find some cheap LED fixtures online.
A good hack is to use some of the led fixtures from IKEA. Here is one I particularly like
it is called "dioder" it has multi color output and can change colors, cycle, or just a single color. It has 4 seperate bars that can be joined in a line or else wired seperately
It has a transformer, but if check, you will see that the LED module actually run at 12volts. All you do then is cut the "wall wart" off, then wire it up to a car battery. (mind the polarity)
If you have cash, go solar, if not, simply plan on having a one deep cycle battery that you can recharge . You can lug it to to the Artery or my camp where I will be running a solar reccharging station. Chances are, the battery will last all week...
hope this helps....