PEX is relatively cheap. Under-slab and slab perimeter insulation is not, and they're not optional if heating with your slab. Looks like 25 psi R10 XPS foam board is $29 per sheet in your neck of the woods. You'd need 138 sheets of the stuff for perimeter and under-slab (R10 required for both). That's pretty much $4,000 on the dot. 3500 feet of 1/2" O2 barrier PEX will run you under $700. You'd then need a 3-loop manifold for the living area (~$200), an 8-loop manifold for the shop space (~$400), a 2-zone heat distribution system (~$2200 preassembled or less if you build your own).
Then you need a boiler. Supply House's calculator suggests you need about 90K BTU. A high efficiency LP boiler in that range runs $2500 and up. If you have the capacity, it would be worth checking your electrical rates vs. LP in your area. A 27 kW electric boiler would do the job just as well and cost $2300, but it would draw 113 amps and require three 60A breakers and a lot of expensive wire.
My experience is that if the building is sufficiently tight and well insulated, the calculated BTU requirements are total overkill. I undersized my boiler, and it still cycles even when it's snowing. That's very anecdotal, though, so don't take my word for it. Also, Supply House's calculator is based off of heating to comfortable home temperature. If you'd be fine keeping the shop zone at a lower temperature than the living space, you could get away with a smaller/cheaper boiler.
Anyway, expect an in-floor radiant setup to run about $11K if you shop deals and install everything yourself and some amount above that if hiring it out.
