With a float that can take the pressure, a very flexible silicone tube and the right connections I can't think of any reason to prevent a modification.
Let us know how you do it if and when your modification works. :thumb:
Not long after posting this I bought the float and not long after that I upgraded to corny kegs so never fitted it. Over a year later I finally used the king keg and decided to give the float a go. The connection between the float end and the inside of the tap inlet was a bit sloppy but I changed the seal for a chunkier O-ring and it seems to have worked well.
The main reason I thought about doing it was to get the beer quicker as the stuff at the top should be cleared sooner. I still felt like the beer needed longer to mature though so didn't really get me into it any quicker in the end. Luckily I had 2 corny kegs to go at.