I like this one but would have wood siding put on. I like the windows.
http://www.capitolsheds.com/sunroom1...rcoal-pch.html
I have a shed from this company:
http://www.leonardusa.com/browse.cfm/2,8.html
The sheds are made like houses and you can get any size, any style, with or without porch, lofts, etc. Obviously it effects the price. I would be more inclined to buy a simple shell and add the features as I go. For instance to install an upgraded window they may charge 3 times more then you waiting and installing new windows later. A deck is nice but you can probably get someone to build it later, cheaper or do it yourself.
I have another 10 X 26 (I think) out there that I paid 7000.00 for. I converted it into a dog kennel, however its huge and could easily be a cabin.
Most shed companies so rent to own so in 5-6 years you own it. If you have a business this really works out because storage sheds are deductible. My new building is only 10 X 15 but I pay 176.00 a month. It has two small lofts I use to store feed but they could have been made larger and especially with a deeper pitched roof.
I'm going to guess that adding walls, electric, floor, plumbing (not septic and well) could be about 4-7K. It depends how fancy you want to get. It could be as low as 2K with a simple set of walls and a compact kitchen
http://www.compactappliance.com/CK30..._Kitchen_Units
The compact kitchens can get pretty fancy and expensive. they've become popular with the smaller living movement.
As for well, septic and electric it would be better if a few people got together and got a permit to handle one well and one septic. I have a 20 X 30 barn I might convert into a community center. I would need to put in floor, walls, plumbing, fix electric & would like to put internet, showers, potties, cooking area, etc.