We are looking at building a small eco cabin and would be interested in opinions as to the most cost effective building method.
The cabin will essentially be a single bed studio with bathroom, maybe 40 to 50 square meters in total.

I will be doing the build myself so really it's just the material cost.

Initial thoughts are polished concrete slab on foam insulation. Timber I beam frame 300 deep filled with mineral wool. Plasterboard inside and timber cladding.
EDPM roof but pitched for internal volume and also cladded with timber in the outsidefor a monolithic apearence.

I have done a few floors recently (power troweled). The concrete costs a bit more but will be less than concrete plus tiles.
Biggest cost is the concrete pump, otherwise I could hand mix the concrete and then tile.

I am an avid fan of Barnwood Builders on the Travel channel where they use reclaimed barnwood to build new cabins. On one of the programs they laid a concrete floor and used silicon molds on top of the wet (coloured) concrete to imprint a log effect. It looked fantastic (if you like the rustic look). Could be an alternative to polishing the concrete?