When I or one of my players comes up with something "weird" that no one else seems to have come up with (logical idea or not), I always start with the same question: "why has no one else thought of this?" I then try to give an IC and OOC answer to it that makes sense and covers most of the possible cases.
In this case, it appears to me there's no magical smartlink because they don't NEED a magical smartlink. They can already do as well or better with spells and/or adept abilities than the smartlink does.
Now, if one of my players came to me with this, I would definitely try to pull it off, but I would make it somewhat difficult and expensive to do. They are, after all, blazing a new trail in magic. First off, the system would have to be entirely magical, no technology involved, which in and of itself would be a design nightmare requiring a lot of gunsmithing skill to incorporate. They're going to have to come up with magical means to operate physical switches and levers inside the firearm. They're going to have to either create new abilities or co-opt existing spells and abilities to operate in ways they weren't designed to. Early prototypes will be clunky and failure prone. They may need exotic materials (can you imagine the cost of a "external smartlink system" made entirely of oracalcum including the lenses then bonding it to yourself?) or unusual methods (afraid you need to make the first ever magical gunsmithing shop).
But I wouldn't stop them from doing it if they wanted to put in the time and effort required. I might even get a run out of it when Corp A finds out about it and tries to steal the "technology." The hardest part is actually working out HOW it would work in order to come up with acceptable rolls, expenses, timetables and needed materials and spells.
