The Barix Barionet devices support 1-wire, not sure if they support the humidity variant, but check out
this thread for some really good information about these devices (I really need to order one myself).
There are now 2 models of Barionet -- the "original" model now called the Barionet 100 (typ.$295) and a new model, the Barionet 50 (around $180).
I have the original Barionet which supports direct attachment of up to 50 1-Wire temperature (only) sensors. I am using several of these and I must say, this is about as painless a wired temperature-monitoring solution as there is. I even put a temperature sensor in my AV equipment cabinet just to keep an eye on things. You just wire them up and then look for the address in your code, because all of the discovery, polling and device support is already in the firmware. At $4 each, and in a tiny TO92 package, you can put them just about everywhere.
If I were buying a Barionet today I would probably get the Barionet 50, which documentation says will support other 1-Wire devices, although you apparently must code specifically for them. I would like a couple of humidity sensors. The Barionet 100 would need a 1-Wire add-on to do this.
By the way, just wondering, why can't we interface a hobbyboards 1-wire hub to the ELK using a serial adapter to get readings from 1 wire devices?
I have given up on the M1 for applications of this kind, because even if you get your sensor physically attached, you still have the problems of (1) interpreting the readings, for which the M1 is not usually friendly or adaptable, and (2) the M1 will not store history. When these factors push you outside the M1 anyway, it's a smoother path just to keep the whole thing outside.
Where your application is looking for the M1 to respond to a temperature tigger point, then an external threshold-trigger sensor with contact closure is usually the best solution.
My interest is primarily temperature logging with some trigger points, such as fan activation, and alarm points. For this I have a mixture of things, which grew haphazardly over time, including M1ZTS on the M1, thermistor-types attached to my thermostats, and the 1-Wire 18B20s, all ultimately managed and stored by the Barionet.