Anything is possible, or it can be if he cheats like he allegedly did in Albania two years ago.
Yeah, what was the whole deal with that? (Unfortunately, even though I can find the old Feltet article on Google, when I try to open it... it's just... not there.)
I'm pretty sure you can only wear the jersey of the country you represent in international cycling, so even if Kloppenborg were to... somehow... win the Danish RR Sunday, he'd not become the Danish Champion, with that title instead passing on to whoever is 2nd.
Now, another question is; will he be allowed to wear the Albanian Champion Jersey Sunday?