Here’s some news I missed (until now, obviously):
The German Aerospace Agency (DLR) has released a 25 m Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) dataset covering approximately 60ºN to 60ºS. The shuttle
is was launched in an orbit with a low inclination and hence the SRTM data doesn’t cover high latitudes. The data are free but you must register on DLR’s EOWEB. The data are produced using X-band SAR interferometry. The X-band data have a 31 mm wavelength contributing to a high vertical accuracy.