I might scan something at some point. I think handwriting is good up to a point, but it usually tries to be TOO specific, and it is terrible at explaining the "why's" of someone's handwriting being the way it is.
For example, someone might consistently write where their margins are ragged, their baselines are not straight but jumbled, and so forth. This says something about their personality... but what exactly? Do they just not care about writing, but care about other things? Were they emotionally disturbed at the time? Are they in a distracting environment? Does the jumbled line carry over to personality traits, or is it just a writing quirk? (Which everyone has.)
It's like trying to say someone is an ENFP just because they have a smiley instead of a dot over their i's. Chances are they aren't T's, but young T girls are still known to play around with that sort of thing from time to time, especially TP. How can one derive a whole consistent personality trait from that sort of thing?
MBTI actually deals with base foundational functions that would reasonably impact behavior across the board and thus has more credibility than a handwriting assessment (because the criteria used to establish personality is actually correlated better to foundational traits), although it still has some problems as AcidGoethe's INTPc thread brought up a month ago or so. I think a Skeptic's Dictionary unfortunately has a bias problem... and the bias problem is inherent in the title itself -- when you define yourself a certain way, you automatically orient yourself towards things in that way rather than another, even if not entirely appropriate.
Handwriting is not bad for some things. Cherie (ISFJ) has picture-perfect handwriting. To her, it's acceptable to write everything the same way every time she writes. Consistency and accuracy and appearance are important. She writes slowly as well. I scrawl in all-caps, in contrast, I never use cursive, my signature never looks the same twice, and when I try to print lowercase quickly, it usually ends up with the first letter or two of each word being recognizable and the rest of the word just being a wavy line -- I usually can't keep up with the flow of my thought process enough to write legibly. So it's like personal shorthand. This makes sense for INTP as a personality, although some INTPs depending on upbringing and need could perfect their handwriting... so it is no clear indication of anything... especially not distinguishing a whole type, for example.