Oh yes, an excellent idea. Probably not something I would personally fly, but you never know.
I'd say make it the size of a large, chunky cruiser. That'll make it pretty tough (though possibly not impossible) to maneuver through asteroid fields and such things. Something like a Behemoth but much, much bigger. Just don't make it one of those ships that has trouble undocking from planets.
My vote goes to no weapons. If it isn't going to have enough to be worthwhile, why bother with them? That's what escorts are for. Not even a CM.
Give it a regular Class 7 Transport Shield slot, but it should have decent armor. Maybe equal or even better than a C-Tran. As slow as it is and with only average transport shields, this armor isn't going to save it unless it has an escort or two around.
As far as hold size goes, it'll need to be major to make flying this hulk and paying the escorts worthwhile. Maybe around 8000.
