The missing european number format (#.###,##) instead of #,###.##) was a real pain for me as well.
I have customers entering number values in different ways via form, so i cannot use number input fields. However since i do have to make calculations and output values on those fields for reporting, I struggled a lot.
I use a text field and thanks to the “number and currency pretty routines” i was able to build something that would allow me to transform a text field into a numeric field to do calculations and then to make it pretty for reporting.
However this only works for values below 1.000.000.
Maybe this will be of use to some of you out there and maybe someone wants to build on that to make it work for numbers over 1.000.000.