If at all possible (should be unless it must break security features in the Logi g510 design), the keys 1, 2, 3 q, w, e, r, etc... should have an alteration in their color to match the significant association to the hot keys defined in game.
I also feel Riot should have taken over this project for you. EA (Electronic Arts) has incorporated a built in plugin into the Dragon Age games, Atari has also integrated it within their Neverwinter Nights 2 and I can assume countless others out there are doing it as well. In fact, instead of assuming here's a link to some references of games whom this plug-in is natively supported. http://en.wikipedia.org/wiki/Logitech_G510
There's countless programmers out there who are looking to start a career (and should be by starting to develop tools). Is Riot gimping out on us? And yes, that was a challenge to Riot. ;P
Realistically, this is not a huge financial investment. In fact, it perhaps could be one of their smallest. The line of support for this is real simple; if it works, "great". If it doesn't, "contact your OEM". To design it... Well if one dude who doesn't work for Riot can make it... Need I explain more?
Also, if Riot were to take over, they could directly incorporate the timers which can not be done unless LOL (League of Legends) is reversed engineered. Obviously, I do not encourage violating the EULA (End User License Agreement as well as copy right laws). In my opinion, if you forgot to hit a button, you wouldn't be kicking yourself because the plug-in at that point is useless. They could also allow you to customize the interface by choosing what you want to display. For example, pushing tab to see how much more time you have before most of the enemy come back from death is kinda hard if your in a fight. Hence, look at G510 for their death timers.
Ultimately, I can see Riot making money from this more than losing. First, they increase value of their product through customer experience (which really isn't a big deal since there are bigger ways to do it). Second, they can advertise Logitech as part of their suggestive brand, like Blizzard does with nVidia (Yes, they make money from this). When its time for Riot to make a new game (and it will eventually be needed), this could save them a step. Additionally, when Riot finalizes their 3D development, they could use the Logi G510 as a real in game 3D calibrator. But here's the biggest factor; once you have a plug-in for one Logi keyboard, it'll be really easy to develop one for the rest. To my best of knowledge, there are at least 3 types of Logi gaming keyboards with displays. There's got to be a nice percentage of people who use it.
Please add your thoughts. It's all about numbers. The more riot that goes into people wanting this, the more Riot will be interested in considering it. Who knows, maybe we'll give this developer a job.