Hi Jeroen,
->Is it also possible to create - one BO with more QA views ? or that I have in my Worklist (OWL-view) for the ->different types (dependant on OpportunitySalesCycle) - have different QA - layouts ?
->Or do I have to this by scripting by checking the SalesCycle (in one Master QA-view).
I am a little bit confused with what you meant. 
1. You can create one BO with more QAs.
2. You can control some layout properties (visible, enabled or disabled . etc) in one QA using Binding or Front-End script.
Best Regards
Fred