I am interested. I like heavier switches, like the 55g, but some springs that could be customized could be of use. For example, I would probably try an extra spring that when added to a 55g dome, it would make it a 60g dome. Just to see if I like it more.
The other area of interest for me is the snappy-ness of 45g switches. I don't mind 45g switches but they are not as snappy as 55g switches imo... especially as they return upward from a key stroke. If there was a spring you could put on a 45g dome that made it as snappy as a 55g dome, that would definitely be something awesome!