Wilbur can read a raw binary raster using File>>Import>>Image Subsection. It will read 1, 2, 4, and 4-byte IEEE-754 float rasters in LSB or MSB byte order.
Wilbur should be able to read some basic file formats such as the elderly USGS DEM format. One of these years I'll get around to including GDAL support via plugin so Wilbur will be able to read many, many file formats.