For financial\accounting, Fidelity Investments one of the biggest (and probably the best) in N. KY.
Toyota is a great company but they run lean. My wife works there as a contractor for their IT dept. When she was hired she was told the chance of being hired on as a full Toyota employee is pretty slim. That said, there was a rumor floating around there (and you know how rumors go) that they are planning on adding a large number of positions this year (~250) but no word as to what type of positions they will be?
Also keep in mind that on the other side of the river from N. KY is downtown Cincinnati. There are a number of large companies there, biggest being P&G. I work downtown and the parking kind of sucks but other then that, it's not that bad. I work 7am-ish to 4pm-ish to avoid the majority of the traffic. I'm in the IT field and I can tell you that decent IT jobs this side of the river are far and few between (even before the IT market crashed in 2000). Hopefully for you, the accounting\finance job market is different?
I don't know how opposed you are to going over the river but keep in mind the UC (and I believe Xavier) offer N.KY resident "in-state" rates. I don't know how their grad schools measure up against NKU or UK but it's another option.
Good luck