Given that you are adamant about no structural wood, I would think that you are looking at several issues. Since commercial buildings are built this way all the time, It should not be an issue. Find a supplier that’s ells premade kits for what you want if steel is the building method of choice. I guess I would look at something like the “Persist” http://www.homeenergy.org/archive/hem.dis.anl.gov/eehem/99/991108.html or “Remote” wall systems http://www.cchrc.org/App_Content/files/REMOTE8-2-06.pdf for the insulation.
The advantage of these is the reduction of thermal bridges through the steel structure because most/all of the insulation is external to the wall cavity. If not alt least look into aerogel metal stud smugglers.
Given the no wood mandate, I would also consider doing the whole shell with ICF. By my back of the envelope calculation, an ICF foundation and wall would be ~ 15 K each Plus footings and 2 poured floors which you need anyway no matter how you do it.
As far as using laly columns instead of a bearing wall, A column will likely require a footing that is ~2’X 2’ a bearing wall will require a continuous footing. The issue is insulation under the slab, and with building sequence. If you want continuous underslab insulation , you pour the basement walls to 9’ Then you back fill with gravel even with the footings, then your vapor barrier, then 2-3” of XPS leaving a small hole where the laly columns will go. With this detail you can pour the slab in the basement when ever you want (after all framing is done). This can make a difference in the plumbing costs because you can have the plumber do it all at once. (cost savings)
With a bearing wall, you pour a continuous footing, then do the underslab plumbing, the put down the underslab insulation, then pour the slab, then put in the bearing wall, then start the first floor joists. The slab will have to rest on the footing so there is continuous bearing from wall to footing so now you have a 18” wide strip under the slab with no insulation. This is not good in living spaces especially with a radiant floor.
As far as needing a crane, if you went with a steel beam you would need a crane, but the delivery company might have it with the truck anyway. if you went with triple LVLs 2 strong people can put them in, one lvl at a time the bolt them together. Alternatively, if your timing is right, you might still have the excavator on site and a good operator can place the beam with that.
The other thing to consider is the cost of the shell is a small fraction of the whole building cost. Usually less then 20% of the total. Your biggest savings is in initial design and having less stuff. I would build the house with all the plumbing centralized so you minimize dvw and venting. This can save big. I would use acid stained polished concrete floors throughout, simple and cheap, (and good looking if done right). I might use cork in the kitchen so it is easier on the knees and feet.
For the trusses, I would use one common truss. Personally I would use a scissor truss to add some angle to the roof, but this increases your interior wall and drywalling costs.
IF you are being cost conscious, consider the following.
1. Ignore the SPF and use cellulose insulation (unless you are concerned about this for other reasons)
2. Figure out how to use simple lighting. For instance one easy way to light a kitchen is to use FL stip lights above the cabinets hidden by the cabinets cheap, easy, efficient.
3. As far as finishes go, if you do the labor yourself, tile can be very inexpensive.
4. You can pinch pennies on cabinets if you are careful
5. Laminate countertops are much cheaper then stone, you can also use granite tile countertops if you don’t mind the labor. you can do granite tile countertops for less then 10$ ft^2 if you do it yourself
6. Plan on using minimal trim in the rooms, use drywall returns on doors and window openings
7. Pick plumbing fixtures made by a reputable American company. Buy them all from the same company ie Delta or Moen. Ignore the European stuff, nice but pricy. Use a simple finish, like brushed nickel.
Things you should not cheap out on.
1. Windows and exterior doors
2. Boiler with outside air supply
4. Heat recovery ventilator.
5. VERY Quiet Bath fans on a timer or humidity sensor
6. Stove vent
7. Toilets Use Toto Drakes
8. Plumbing fixtures
Also, don't underestimate the time it takes to build. Mentaly prepare yourself to work on the house 7 days a week nights and weekends for a couble of years to realize you dreams. Make a list of all the friends you have that have building skills and or are strong. Plan on using them all, but rotate through them so you don't burn them out. for stuff that requires lots of manpower like setting trusses or raising walls, make sure you are prepared ahead of time so when you have help, you can use it most effectively.
I know, I am moving in this weekend to my new house, 15 months and 3000 hours of labour and after I broke ground.
The other thing i think is very important for owner builders it to make sure you are doing the framing and exterior work when you have maximum daylight to work (and it is warm). It is a big sprint to get the builidng enclosed and water tight. Once you are dry and inisde, you can work off lights and a generator much easier.
Have fun and take pictures