One of the more interesting and powerful multi-sensor combinations is to use a boat as a platform for LiDAR and multi-beam sonar. With this integrated approach you can capture the near shore and the underwater bottom surface map simultaneously.
In this excellent presentation by James Coleman from David Evans and Associates he provides a detailed look into the use of this powerful technology. In this case he is using a Riegl Z390i with a Reson 8101 multibeam sonar. The latter has 101 individual sonar beams that combined provide 150 degree x 150 degree coverage.
This certainly does not represent a small investment, but if you can find the customers this is an interesting niche.