The developers of SimPowerSystems have recently released an example of a new timestamped solver. They presented about the technology briefly at NI Week this year, but this is the first public exposure and discussion of the solver.
http://www.mathworks.com/matlabcentral/fileexchange/48381-buck-converter-increased-accuracy-and-simu...
The implications of this are pretty interesting for real-time simulations of power electronics systems. The approach uses a very high-speed loop in FPGA to accurately capture digital events and then passes the timing of those events to a more traditional solver running on the CPU of the real-time test system. This timestamping allows simulations to be run at CPU speeds but have the accuracy of something run with a much smaller timestep.
If you are a user of SimPowerSystems, take a minute to look at this apprach and try it out with a couple of models. I would also encourage you to post feedback or questions on the Matlab Central cite. If this is interesting to you, please make sure you leave positive feedback on the example.