Have you considered making some artefacts for objective markers? Mine were just slapped together out of a bit of greenstuff and painted up in weird colours. Though I guess regular stacks of grates and guns work for objectives too to be fair.
Currently playing my way through a CoP game at the moment, so those artifacts are definitely familiar. In 25mm plus (or, maybe, even 20mm) or larger, the artifact models make sense. My chosen scale is 15mm so, while I'd like to make up some similar models, I'm thinking the effort wouldn't be worth the appearance of the final item... :/