I just spent the last 6 months moving 100 VSS repositories to TFS, so I feel your pain! I did this only in TFS 2008, but there is no reason why it should not work in 2010.
I would consider unreasonable merging as a last resort, since you will stick to command line sinks.
The trick is to establish the connection between the branches before importing the code.
(As an example, I use a simple branch of one dev, but you should be able to use the same theory, regardless of the number of branches)
, "", "dev" . .
"trunk" "dev" .
"trunk" "dev" , , TFS , , , . , ( , "dev" , , , , - , )
2 , , .
dev, , "trunk" "dev" , "dev" , , , ""
, ( 2) "" , ..
$/oldTeamProject/Devbranch $/NewTeamProject/DevBranch $/oldTeamProject/Trunk $/NewTeamProject/Trunk
$/NewTeamProject/Trunk $/NewTeamProject/DevBranch
TFS 2008, ( ). , "" , , . , , : -)
, TFS , , "dev" . , . , . , slike, , .