I wish to inform you that I found the answer the question regarding the caseload in Colombo VO in data.gc.ca site.
It contains several very important details about immigration data.
I am going to summarize what is relevant to Colombo VO
Pending Case Load as of 1st July 2011.
....................................................
Appl. Rec'd before February 27, 2008 (Pre-C50)
Selection Decision - 460
Final Decision - 245
Total - 705
All MI-1 : Appl. Rec'd between February 27, 2008 and June 26, 2010
Assessment for Eligibility - 138
Selection Decision - 293
Final Decision - 120
Total - 551
Pre MI-1 : Appl. Rec'd between February 27, 2008 and November 28, 2008
Assessment for Eligibility - 4
Selection Decision - 21
Final Decision - 29
Total - 54
MI-1 : Appl. Rec'd between November 28, 2008 and June 26, 2010
Assessment for Eligibility - 134
Selection Decision - 272
Final Decision - 91
Total - 497
MI-2 : Appl. Rec'd after June 26, 2010
Assessment for Eligibility - 65
Selection Decision - 118
Final Decision - 99
Total - 282
Looking all the federal case worker applications
Assessment for Eligibility - 203
Selection Decision - 871
Final Decision - 464
Total - 1538
Judging by the number of cases processed by Colombo VO has processed 922 persons and issued 599 visas during the 12 months ending 1st July 2011.
This means they should clear the backlog within two years.