Omni for stuff in the support role is just plain crazy. There's an OmniTrain in the first VA, Omni Pods take half an hour per location to change, for railways this is SLOW, and even once you've changed the trains config the train still needs to be loaded, and I'm paying a 25% markup for this? What are you taking?
That doesn't even mention the other problems: Would you ride around in what amounts to a cargo module on a flatbed car? To say nothing of the OH&S issues that would likely see you shut down
Who says you can't load a cargo pod before you attach it?
Also, a podded MASH unit (for example) isn't a bunch of doctors in a cargo container. It's a fully-kitted out field hospital, complete with diagnostics, surgeries, and recovery areas. Ditto for Communications Gear and other inhabited loadouts.
I guess you're right that for many functions you just pre-fab a bunch of mothballed conventional trailers and attach them as needed. The rules aren't friendly to this because each trailer counts as a vehicle and needs at least a Tech team to handle maintenance, whereas one team can handle all an omni-trailer's pods. But I'll admit it's a stretch. At least this way you're only paying the omni penalty on the pods and the trailer's structure. Everything else is paid for as a conventional Vee.
The main application I had in mind was for examples like this (inspired by one of the colony threads). You roll up to a construction site. You demolish the old structure if applicable. Then you clear the rubble, prep the foundation, and begin assembling the building. Normally, that's several different vehicles which mostly sit around eating up maintenance when their function is not in use. With omnis, you use one vehicle and reconfigure after each phase of construction. You schedule your construction so it fills in between seasonal roles like agriculture. One vehicle, one tech team, one engine, one dropship bay, but many roles, and you're not even fully paying the omni cost. (Though again there's your point that, but for the quirk of rules that treats trailers as vehicles, why not just field the trailers?)
Good thoughts, and I appreciate the input. It's funny that a "hey here's an exploit" can be a "why the hell is this going to help you?" :)
Anyone have any thoughts on the omniVTOL mechanized battle armor?