During my career I came up with a novel approach to electronic circuit simulation that particularly applies to large signal (Power) electronics. The approach is described in the following papers.
If anyone has written an electronic circuit GUI then I would be interested in trying to put it together with my large signal circuit modelling program LARGESS.
The ZIP file below contains the LARGESS software, compiled for Windows, together with a ReadMe file describing how it is used. I can be contacted via the LTspice usergroup if anyone has problems running it.