Only if you use a system where the text will be smaller in higer resolutions can you get perfect pixel to pixel matching. And only perfect pixel to pixel will be perfectly sharp.
Yes I totally understand this. It makes sense to have multiple bitmap fonts to cater for certain scales of resolution. I don't see how else you can get around this.
As regards to my widescreen query, I was talking not just of 5:4 and 4:3 but also of 1920x1200 screens and other such strange shapes.