where to buy a butane portable in NH?
You might consider an Iwatani butane stove. This type stove is very common for tabletop cooking in Japan, for example, is safe to use indoors, and is inexpensive. In the SF Bay area, you can find the stoves for as little as $25-26 at local Asian supermarkets. I don't recall that many Asian markets in NH but perhaps you can seek one out on your next trip to Boston or find a good source and price online (there are many onine vendors so try google. also - you will probably see prices much higher online - perhaps $45-50).
Butane canisters cost less than $1.5-2 hereabouts (more online) and last for a couple of hours or more at moderate flame levels. The ZA-3 model puts out 10K BTU, the 35-FW will generate 15K BTU. Turn the dial and auto-ignition fires it right up. The cooking surface is large and stable. The stove is ideal for picnics. Try iwatani.com for more information.
I have the ZA-3 and use it frequently. It is reliable, efficient, and very well made. Both units have a patented safety valve (see the website for info). I found the 10K output provided plenty of heat for cooking. I suspect the 15K unit is a real blowtorch.
I've seen a couple of other brands (one foreign for about the same price, one domestic for much more) but don't believe they are made to this quality level.
Just to clarify - are you really looking for a butane stove? The only butane stoves I'm familiar with are little anemic units for doing tableside cooking such as Bananas Foster, and 10,000 BTU really isn't much heat output. It sounds more like what you want is one of the LP (propane) outdoor cookers that people use for frying turkeys, among other things. The heat output of those units is usually several times 10,000 BTU. If that's what you want, then RShea78 has provided one source. They're typically available also at outdoor stores such as Cabelas or Bass Pro Shops. If you're in southeast NH Kittery Trading Post may have them as well.
I have pitched mine because the fuel is so pricey and indoor use is frowned upon by the fire authorities.
Perhaps you need to fill us in on your plans of use, such as indoor or outdoor use, and if you checked into local codes if used indoors.
I went with an outdoor multi-ring burner that I can attach my LP grill tank to. Commercial electric glass hotplate for indoor use.