Scale jump and try some of the 15mm drones from Ground Zero Games' Stargrunt range, perhaps with part swaps - the weapons are all separate and easily replaced with sensor/commo bits from the tank packs. The spider drones are about man-sized in 15mm so they good small bots in 28mm, and they'll fit a 25mm base. The larger four-legged drones and gunplats could also work well (especially the big gunplats - they could be rigged with a kitbashed stretcher as medic/casevac droids) but they won't quite fit on a base. Then again, they don't need a base, so maybe workable anyway.