Updated to 1.17e.
@tollworkout, unfortunately, scan data is referred to not modifiable scang.dat file, consisting of 4x4 pixeled data. There's no other way of adding custom scanner sprites, except for editing scang.dat stored (as well as loft.dat). MCD data (62bytes) can't store 16 bytes of scanner sprite.
It is possible to modify engine of openxcom, to use "custom" scang sheets for values, say, beyond 1024. But engine should be able to support it. And I guess there was no hard request of this.