René Péter-Contesse and John Ellington notes that the "Ancient of Days" in Daniel 7 "is clearly God himself."
René Péter-Contesse and John Ellington, A Handbook on The Book of Daniel (New York: United Bible Societies, 1993), 186
Ancient of days: this expression designates an aged person and one who is therefore, in the biblical culture, considered especially wise. In the language of the vision this “old person” is clearly God himself. But the style of the vision would be betrayed if this were clearly stated in the text (as in LB). This information may be given in a footnote. Some other nonliteral renderings of this expression are “the (or an) Ancient One” (NAB and NRSV), “the Ancient in Years” (REB), “a primeval Being” (Mft), “The Venerable One” (AT), “This-One-Who-Endures” (Lacocque). Some languages will have a similar expression that can be used to refer to God without using his name.