Well the HD IP cameras are often 1080P and also feature IR illumination for use at night. The PoE type would just require a single cable for power and video but at 100m you would be on the limit. I would suggest using good quality CAT 6 cable (23AWG if you can find it). Not sure which HD SDI camera you were thinking of but for IP something like the Trend or Maplin 1080 PRO security cameras are fantastic quaity and easily interface to their NVRs