Surly makes several forks for the Pugsley and Moonlander with and without offset and with 100 or 135mm spacing... you can run a standard 100mm hub or in the case of the Pugsley the front spacing is 135 and it uses a drive wheel. It provides for a second drive be that an SS or fixed cog, cassette, or if you did not mind the weight, another IGH.

Swapping the wheels is not something you would do all the time as it isn't that quick and easy because the combination of rear facing drops and a disc brake in the rear makes extracting the rear wheel a little more time consuming (the brake has to be removed).