I run the BAC 1-11 website and can confirm to all of you that want any further information to check out
www.bac1-11jet.co.uk
The details on this site are more than purely "speculative" as are those on the BAC 1-11 Forum at Yahoo Groups that I also run.
I can confirm that there are approximately 20 or so 1-11s still flying.
These are as follows:-
Air Katanga - 9Q-CSJ - Lubumbashi DRC (possibly grounded by now)
Business Jet Access - N999BW - Dallas Love Field
Vigo Jet - XB-JZX - Puerto Vallarta
Grupo Adelac - XA-CMG - Toluca
GST Aero / East Wing - UN-B1110 - Almaty
ITAB - 9Q-CDY - Lubumbashi DRC (Used by compagnie africaine d'aviation)
Libavia - 5A-DKO - Tripoli Mitiga
JetEx Flight Support / MIA Airlines - YR-CJL, HRS, MIA - Bucharest Baneasa
Northrop Grumman - N161NG, 162W, 164W - Baltimore Washington
QinetiQ - ZE432, ZE433, ZH763 - Boscombe Down
Romavia - YR-BRE - Bucharest Otopeni (Government aircraft)
Royal Air Force Of Oman - 551, 552, 553 - Muscat Seeb
Select Leasing Inc - N111JX, N200EE - Waukesha Crites Field
Trast Aero / Aquiline Intl - EX-086, EX-103 - Bishkek, Kyrgyzstan
Total 24 airframes although several of these have not been reported in service for quite some time.
I hope this helps.
Please check the 1-11 website for any further updates or join the forum!