Where in South Central WI are you? I'm in Madison and purchased my Hearthstone insert (LOVE IT!) from Top Hat in Madison. They've got a second showroom in Baraboo, which is where their main warehouse is located.
Decent guys to work with - they were happy to let me buy and do the install on my own but I had a lot of things worked out before I talked to them so they knew I wasn't going to burn my house down.
Top Hat may be a bit on the pricey side so look around.
I don't know what you are looking for as far as aesthetics - maybe you want to hook a wood burning furnace into the ductwork. In that case, there are several Daka (sp?) units for sale on the Madison Craigslist on occasion. I don't know if they are worth the sweat to move and install them but if you can get them at a discount, what the hey, ya know der Eh!? (sorry, cheesehead accent coming through)
Is your oil burner a forced air system? Gravity? Or is it steam/hot water heat? There are ways of augmenting all of it.