Dave, first of all your electrician will run the wiring according to code - regardless of what you suggest to him. The only thing he'll consider is wire that is sized bigger than required that will physically fit the outlet or breaker. For example, he won't accomodate you with a 30-amp branch circuit breaker, floor outlets, 10/3 wire with common neutral or a secondary ground. All are no-no's with respect to NEC and most local codes - he'll explain why.
If you want an isolated ground, ask for "hospital grade" wiring, aka "Type MC" cable. This aluminum-armored cable comes with the extra green wire, that is 10/2 MC will have a black white AND green whereas 10/2 "regular" (or BX) will only have black and white. Regular BX 10/3 will have black, white and red - no green. Can't use RED for ground with most codes. If you're using Romex, then the green comes with the wire - that is, 10/2 romex has black, white and green.
The use of 10/3 wire is intended to be used in switched outlets where you want to continue the circuit power independent of the switch to the next outlet. Commonly used at receptacles that are switched on by a light switch and ceiling fans with separate motor and light control. Sometimes it's used by stingy homeowners to run two circuits with one neutral - saves a run of cable.
Installing a sub-panel is a very good idea if you can swing the cost. Your electrician will be able to recommend the correct size for your application. I would overkill the wiring to the subpanel by sizing them according the the panel rating. E.g., if it's a 100-amp subpanel run three #3 wires in 3/4-inch EMT, if it's a 60-amp subpanel, run three #6 in 1/2-inch EMT. Again, trust a competent electrician above all else.
If you want an isolated ground, ask for "hospital grade" wiring, aka "Type MC" cable. This aluminum-armored cable comes with the extra green wire, that is 10/2 MC will have a black white AND green whereas 10/2 "regular" (or BX) will only have black and white. Regular BX 10/3 will have black, white and red - no green. Can't use RED for ground with most codes. If you're using Romex, then the green comes with the wire - that is, 10/2 romex has black, white and green.
The use of 10/3 wire is intended to be used in switched outlets where you want to continue the circuit power independent of the switch to the next outlet. Commonly used at receptacles that are switched on by a light switch and ceiling fans with separate motor and light control. Sometimes it's used by stingy homeowners to run two circuits with one neutral - saves a run of cable.
Installing a sub-panel is a very good idea if you can swing the cost. Your electrician will be able to recommend the correct size for your application. I would overkill the wiring to the subpanel by sizing them according the the panel rating. E.g., if it's a 100-amp subpanel run three #3 wires in 3/4-inch EMT, if it's a 60-amp subpanel, run three #6 in 1/2-inch EMT. Again, trust a competent electrician above all else.