Hi,
as a by-product, I created 'The Dirtyer':
http://toolserver.org/~ti/dirtyer/
Paste any toolserver-tile-URL (e.g. tiles/bicycle/13/4290/2868.png)
and it will mark the tile itself and up to three generations of
offsprings as dirty (where one generation is the four tiles for the
same area on the next zoom level). So if OSM data changes, you don't
have to request a redraw for every tile yourself.
I restricted the maximum depth to 3, so server usage shouldn't be too
high.
Regards,
Thomas
PS:
What I'm not sure about: Is the tile redrawn immediately when it's
marked as /dirty or only with the next request?