Most model plans for steam engines tell you to use compressed air to run the engine. Most model engine shows provide compressed air and strictly disallow use of live steam. Recently, I was digging for some information on John Ericsson's Hot Air engines and ran across a piece from the New York Times dating back to the 1860's - it was an ad for the Ericsson Rider engines. They listed five reasons you might want a Ericsson Hot Air Engine instead of a steam engine; number 5 was insurance. What? Yea, insurance. Without a boiler to worry about, your insurance rates did not go up. Or if you already had a steam engine, your insurance rate could go down by getting rid of it.
No two ways about it - boilers are dangerous. But I think with modern technology including improvements in materials technology and electronics, boilers can be built safely. 
One of the most interesting designs I've run across is that of a flash boiler. The concept with the flash boiler is that you have a coil of pipe through which you flow water and heat it fast and furiously so you get steam quickly. Without a tank under intense pressure, the risk should be reduced. The pipe serving as the flash boiler is of course under considerable pressure; but the quantity of steam at any given moment is a fraction of what a traditional pot boiler might have.
I ran across some plans for flash boilers in a book written near the turn of the previous century. I reviewed this book here.