For a 1400 Square Feet, it shouldn't be a problem to modify something and make it work, if you already built your house on a slope, it's another plus to have a nice coal bin with an incline, I always wished to have such a situation, I have built a bin last year for an old friend of mine, imaginne one of those cement transport truck, with the container ( not turning ) having its top sliced horizontally, it worked really nice, that he was able to completely empty the bin, without having to go inside it and shovle anything, it held 4 tons, and few people who watched me build it were taking bets whether it would crack under the load, it held up very well, its lowest point of exit was off the floor, about 18 inches, it's about empty now, ( he is using oil again temporarily ) . So I'll be able to take pictures, and possibly a video.
I have seen many hand fired stoves as boilers, and they may be the answer to your needs, you just have to keep on looking , if I find one, I'll send you the link.
Converting a stoker to become a boiler, isn't too hard these days, I have turned one of my stokers, into a continuous hot water source, I did the testing Sep-2009, I did not measure however, how many GPM I have reached, but it was plenty . I am about to start using it full time summer and winter. I figured 15 to 20 Dollars a month shold be the maximum it would cost me to have all my hot water needs.
The one disadvantage of a stoker, is the fact you can not burn wood in one of those things, and we all have at some points some wood we would like to burn.