I left it there for about an hour, no change.
There also isn't anything to boot into, I wiped /system/ and /data/ before unlocking the bootloader.
I was trying to get S-Off and it didn't work with CyanogenMod, so I locked the bootloader and tried to install an RUU and of course, that doesn't work if you don't have S-Off, so I wanted to unlock it again and install a sense based ROM after that, but that's where I got stuck in this bootloop.
In retrospect, it probably was really stupid to wipe those partitions before. Not sure what I was thinking at the time :/
I'll try Ubuntu tomorrow and I'll try it with a brighter light, maybe that works. Otherwise I just have to send it in. Worst that could happen is that they somehow get into the bootloader and discover that it says Tampered, but at that point they can just send it back and with a working bootloader I can fix it myself.