Well, it'd be trivial to modify an existing software FM receiver to have a larger audio bandwidth (typically that means a larger control loop bandwidth). The hardware cost would actually be below 10€ with a china-imported RTL-SDR dongle.
For example, GNU Radio comes with a simple, parameterized FM receiver and you can set that to basically any bandwidth you'd like. In fact, it comes with three from which you can choose:
I've quickly built this for you, in hopes it'll be helpful at understanding the ideas. You shouldn't be expecting the same output from the three, but I hope the whets your interest in SDR; yes, that's three different FM receivers; and yes, that's Not Much WorkTM to have something to play with.
Note that the question really is where you'd get the FM signal, and what that signal actually should contain – from the top of my head, very wide FM doesn't make much sense in many potential radio channels, signal model-wise, so I'm a bit curious what your application is. Please don't build yet another PSK-in-Audio-over-FM transceiver. These things were spectrum-wise a bad idea from the start, and given the existence of SDRs there's no excuse to build one in 2018 (as you don't need to pack your data into audio for FM transmission to use affordable hardware anymore).