Yeah they would definitely make the scope too high. Maybe someone will come up with an adapter to side mount it or something. I wish I had the know how and the tools to try and make it work
...Hmm, but what if some enterprising body made an oval magazine? Same height as the standard, but just sticks out further and holds the pellets in belt of sorts instead of the rotary holder? If the FX indexing system needs something to engage, that could still be built into it. Well, for that matter, what stops a person from doing some sort of belt magazine of whatever length? I think it would still need something wound up to satisfy the indexing/loading action, but the gun wouldn't know the difference after that as long as you don't block access to the side lever. Unlike the BSA R10, the FX lets you get at either side of the loading port, so you could do some pretty weird things...