You may see it already on the L4D Classic server, if you brake a Box, some items will be droped. Now, i overworked the plugin to a L4D2 Version. It do the same there, only the new items are add. so its on all server exept the gungameserver. so look out for boxes, they have anytime nice supplies inside. and if you find a bigbox you will have more items.
i was first think to add M60 and Grenadelauncher but on some maps there many boxes and so to many heavy guns spawn. also in l4d2 will not drop pistol and desert eagle. may i think about to ad them later.
This idea was do by Timocop and me some time ago. Have fun.