Another idea I’ve had over the weekend is to use a CO2 canister (such as those use in airsoft) to occasionally blast the inside of the blade/led strip girder with gas. I don’t know how much gas is in those canisters but it should be able to quickly cool a warm metal tube/profile. You could build a system to quickly change canisters that is based on airsoft guns.
I had one other crazy idea based on something I read on here which I’ll post later. It’s rediculous but you probably wouldn’t have to cool it - even at full brightness.
Edit: posted it here.