Something entirely different I'd appreciate in TS would be LMS 10000/10001, the first mainline diesels to operate in Britain. Since the prototype Deltic DP1 pack seems to be quite popular on Steam, it's only a natural fit that these English Electric powered dinosaurs should make their way into the digital world. An ideal pack would include the locomotives in their original LMS black with raised lettering, and their later appearence in the BR years, maybe even a weathered variant.
Great suggestion prrsteamfan, why do you like these locomotives and what scenarios would you have for them?
IIRC only one of the twins ever carried LMS livery since 10001 entered service after Nationalization. There's a good vintage film about their construction on YouTube. It genuinely infuriates me that no attempt appears to have been made to preserve these. Mind you the aforementioned film shows asbestos being sprayed around the engine bay so it's possible that had something to do with it- in the '60s though? All for this BTW- I like something with a bit of novelty value. How about the Fell Diesel-mechanical locomotive which had six engines?