We had someone asking for one at work so I had a look.
Long story short, could not find one from K&N, Pipercross, HKS, or indeed Green.
Saw a few on Ebay but they didn't look great tbh.
I genuinely wouldn't bother removing the factory airbox. The design of it looks pretty good already. If you look where it's drawing air from that's about right.
I think you'd probably lose some low-end going to a big cone filter-ey thing vs that.