Hi Harman,
Yes you can have Tradeshow as Portal Theme and CORBU if supported in ECC as theme for all WDA applications.
To check if CORBU Theme is available in the backend ECC system go to SE38 - WDTHEMES
it will list all the themes in the system.
You should also see the themes in SE80 - Mime Repository - navigate to UR folder and Theme...(explore under Mime repository you should be able to see the theme.)
In SE80 WD_Global_Setting - goto Change and change Stylesheet URI and ensure the iView property Supply Portal Stylesheet is set to no.
Hope this helps.
Cheers-
Pramod