Nicole,
You make it so difficult for us to advise you!! None of us want to see you alter your style of photography, but we all know this type of camera will do that to you when you use it: we've been down that road too.
Using LF will force you to seek a new direction because it forces you to take a more deliberate approach to photography. That could be taken very wrongly, I know, but it's not meant to imply your photography is not deliberate now - it's just going to be more so when you play with a big camera.
I say go for it. If it's 10x8, look for a second hand Kodak Master II or a new Tachihara triple extension or Shen Hao. All those cameras are compact enough for the Vespa. Choose a focal length suited to your expected subjects for this new toy. Don't be too concerned about how sharp it is - you're probably going to be concentrating on contact prints from 10x8, so you are not likely to encounter any sharpness issues aside from depth of field limitations.
Budget for a tripod - the lighter the better if you must Vespa it. I know you want to hand hold, but that's not likely to work unless you make a special bracket. It's going to be even more difficult if you insist on natural light (refer to original post), since ƒ8 will be a fast lens with no DoF. Expect normal working apertures of ƒ32.
I know you will love this format. You are likely to use it for different subjects to what you shoot now. It will compliment your usual style and help you focus even more carefully when you switch back to roll film cameras.
If you can wait until I get to Perth in ~6 months, I'll happily lend you my Tachi for a week at a time. It's only 5x4, but it's still fun. If you're nice to me, I might even send you my Crown Graphic (on loan) for a play - again, only 5x4, but enough to whet your appetite .....
Of course, having said all of this, as a male I still respect your inalienable female right to change your mind on this subject
Cheers,
Graeme