Dear MEMS community,
    Here's a summary of responses to my original question of glass drilling
technology.  I have found nine possible methods for machining glass wafer.
I also list contact info or service links forwared to me.  Hope this helps
to people who are interested in this issue.  Thank you all for your inputs.

Glass machining methods,    potential for large production,    smoothness,
conical or tapered profile
1. Mechanical drilling             no
rough                no
2. Ultrasonic drilling                yes
rough                yes
3. Laser drilling                       yes
smooth             yes
    (eximer and CO2)
4. Micro-sandblasting            yes
(?)                      yes
    (Crystal Mark, Mems, Inc)
5. Ultrasonic drilling w/EDM  ?
no                      no
    (Prof. Masuzawa team in Tokyo University)
6. FIB                                       ?
smooth              yes
7. FIB enhanced etching        yes
unknown           unknown
   (Norsam Technologies)
8. Selective etching with photosensitive glass (Foturan)
                                                  yes
unknown           unknown
9. chemical-assisted laser etching
    (Revise Inc., DARPA project)
                                                  unknown
unknown           unknown