Damien,
It's a fairly common practice, if you have a remote
tuner handy. How well it will work depends a lot on the
tuner, if it can handle the impedances presented to it.
Not having a remote tuner, I do about the same thing except
the coax run is very short and the parallel feed line is
very long (lol). Are there any 'problems' with doing it
this way (or your way)? Sure, the same ones you see in
almost any antenna installation. There are frequencies
where the RFI is more objectionable than others. What
those frequencies are is going to be different for every
installation / situation, so you'll just have to try it
and see. Good luck...
'Doc