Please include all who were approached and maybe those who auditioned and later became famous.
A 1987 memo between Paramount execs gives the following names:
- Mark Lindsay Chapman
- Eric Menyuk
- Kevin Peter Hall (also for Geordi)
- Kelvin Han Yee
Note the obvious absence of any actors that actually were cast as regulars on the series and, of course, Brent Spiner!
UPDATE: Memo was uncovered by Letters of Note a year or so ago.