If you want a stroker evenfire crank, you can probably get a price quoted of $2000 or so, and maybe a 6 month wait. You may even receive it after 6 months. Or you may wait another 6 months. Stroker oddfire cranks are difficult to find, as most oddfire cranks were for the ASA racing, and were usually 3.400" stroke.
To tell you the truth, a mild motor *doesn't* need the cubes. You'll generate MORE torque... gee you can't make torque in a Syty? You got problems...
Unless you are shooting for more than 800-900 hp, you shouldn't even worry about building a stroker motor. Keep the stock crank dimensions, and you can use easy to find parts... regular length rods, common pistons. Make a strong motor that spins a bit more RPM with better VE. With a well tuned combo, you will have more power than you can use... believe me.