Actually I do vaguely remember a redpost talking about implementing something to fix the problem of not being able to report, which is supposedly going to be released with the new Client (aka: soon™)
Two things to consider in the mean time:
Why did he decide to troll? Any specific reason? Because most people that claim that they will troll are just pissed about something that didn't go "their way" during champion select... and those guys suprisingly often dodge themselves. They just attempt to get others to dodge so they don't have to.
I understand if you're not willing to risk it, but I usually play chicken with those guys. I'd say they dodge themselves about 80% of the time. And in the remaining 20%, most of them don't even really troll (outside of the possibly horrible champion picked for their role).
Secondly: The amount of LP you gain/lose per game is defined by your hidden MMR and your tier. Say your MMR is higher than the average player on your tier, you will earn more LP and lose less.
The dodge penalty only applies to LP, your MMR stays the same. So ultimately after a bunch of games your LP/Tier will "catch up" with your MMR. The idea of the punishment is only to make sure people cannot constantly dodge until they get a perfect composition in order to climb in rank.