The higher end ones can - they even have an option to choose between PEF and DNG for RAW format. This is what I'm doing as well, but the DNG files take 20-30MB

The higher end ones can - they even have an option to choose between PEF and DNG for RAW format. This is what I'm doing as well, but the DNG files take 20-30MB of space, even at pathetically low 16MP (/s, high quality 2MP was enough for A4 prints...) resolution, and disk space is not THAT cheap once you want local and offsite backups as well.