Make custom beacons

Of course it'd be possible, you just have to figure out the best way to go about doing it. You can make it look completely different and do whatever you want as well! You just need to make a custom block (or block(s)), and add specific procedures to run to build the beacon's effects.

Ok, but how do you detect if a player is in range?

There are get entity in range and is entity of type in range procedure blocks