Good idea!
Thanks for the suggestion.
So with last beta http://beta.plantuml.net/plantuml.jar
you can now have:
@startuml
skinparam SwimlaneTitleFontColor red
skinparam SwimlaneTitleFontSize 18
skinparam SwimlaneTitleBackgroundColor #EEE
skinparam SwimlaneBorderColor blue
skinparam SwimlaneBorderThickness 4
|swinlane1|
:first;
:second;
|swinlane2|
:third;
if (foo) then
:something;
endif
|swinlane1|
:back to swinline1;
|swinlane2|
:back to swinline2;
@enduml
Is this what you were expecting ?