Hi, I'm new to these forums but have learned so much from lurking already. I got one of these lanterns (model no. is BDBEAM-B, $7.88 at my local Wally World) and love it. (The picture is to make sure you're talking about the same one.)
I'm not much of a modder (yet?), but I did put a Mag-num Star Xenon 4D bulb in it and it seems brighter now (certainly whiter anyway, and a cleaner flood). I put the original one in the spare bulb holder on the underside of the panel that holds the bulb in place.
I also took out the 4D battery adapter that came with it and put a Rayovac 808 6v lantern battery in it. They are cheap F-cell batteries (about $6) that should really extend the runtime.
A factoid: these lanterns are actually made by Rayovac.