Just released a new version of Amiri font, This is a mostly cleanup release, but now the font is more or less in a good shape and can be usable to some extent.

Update: kerning under windows (Uniscribe) would break mark positioning in 0.012, just released 0.013 to fix this (hopefully).

Amiri 0.012 (2011-04-26), A Long Night
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* New glyphs:
  - Add localised Urdu and Sindhi digits ('locl' feature).
  - Add tabular numbers feature ('tnum').
  - European numbers and some punctuation marks from Linux Libertine.
  - Add at sign with experimental Arabic variant ('locl' feature, too).
  - Add triple dot punctuation mark (U+061E).
  - Add middle dot (U+00B7).
  - Reimplement الله igature properly and added فلله ligature; the code now
    much more careful on when to activate this ligature.
* Cleanup:
  - Massive cleanup removing tens of too similar glyphs, making the font more
    unified and consistent.
  - This cleanup results in more contextual variants that were missing before,
    yet the font is smaller not larger.
  - Scaled Tashkil marks down by 80%, they are now smaller leading too less
    mark collision.
  - The Arabic digits are more polished.
  - Misc. mark fixes.
  - Less use of exotic OpenType features to work with even more OpenType
    implementations.
* More kerning pairs.
* Bug fixes: 3234138, 3110760, 3087332, 3073139, 3211187, 3211239 and 3078741