Power12-- Where are you getting 10% today and still have liquidity? Your arithmetic is correct if you can get 10%-- I sure in the hell don't know where it is at-- and I have been looking.
I would keep it in cash-- maybe the .82% at the bank-- I know, not the wisest way, however, I want to be able to touch the $100K if I need to. Yes, the car is paid for, the house is currently a rental, however, we will probably build/buy a smaller house in the future. I have all of the toys that I need/want-- sure, could by some things, however, bought a new mandolin the other day and have had fun with it. I know, a boring engineer's life.
The only place to get a good return today is the stock market, but you need to have the tolerance for risk. If you need the liquidity in an emergency, it may take a few days to get the cash. Open up an online brokerage account, link the brokerage account to a bank account to allow timely electronic transfer of funds. That is how you get the "potential" for high returns and be as close to liquidity. The drawback is you must accept the fluctuations in the market and not panic. Time is on your side, unless you are in retirement or close to it. Don't invest in the fad stocks like google, facebook, etc, they do not pay dividends (High risk, high return). They are risky and your return is solely dependent on stock price. Don't invest in the stocks that do not increase in price, but return a dividend (Low risk, low return). You should focus on the stocks that do both, a nice dividend and constant price increase (Moderate risk, Moderate return). This is usually your balanced approach, nice dividend and some price increase.