Just an FYI, even if your factor is 10^7 so you can "keep" an extra place for rounding, Int64 will let you work with values in the 900 billion range. If you might need more than that, MBS or Bob's plugins will do the job.
You can create a class that will mostly work like the native Currency type using the Operator_* methods. Internally it only needs to do standard integer math against any value multiplied by your factor. When it returns a double or integer, it needs to divide by factor first, and you have to implement your own Str and Format functions. I'd say this would take about 2-3 hours with testing, but you'd have something reusable for future projects.