Ok I'll have to test that, it used to work in Crysis Wars. Like imagine I wanted to change map to one called "Jump_3". The essencial commands to set up that would be "net_mapdownloadurl hxxp://my_url.me/Jump_3.zip", "sv_gamerules ItsGameType", and finally the "map Jump_3" command.
To ignore the levelrotation.xml I would just issue that logic of commands once the round time had reached 0, or close to it, being that the game stays in the final score screen for a while. Eliminating the levelrotation.xml would just keep the server waiting for a map too at the final score screen.