I have been in touch with Emma Drakeford at Stapleford in relation to doing the Multi-IR on the Twin Star and she stated that the whole course could be done on the Twin Star, with one hour on the schools Seneca as part of differences training. Obviously this one hour is only realistic if you have an MEP on a piston engine aircraft like the Seminole or Seneca, but still, that's what hour building is for!
Personally, I'm with Moggiee on this one. For us wannabee airlines pilots, doing a Multi-IR on a Seminole, an MCC on a 737-200 and then having to convert to something like a 737-800 (i.e. The Ryanair route, for example) makes less sense than embracing new technology like the DA-42.
Anyway....the debate continues...
Simon.