This has been a big thorn in my side regarding OS X: Not being able to print to classic only printers (like my Sony UP-DP10 photo printer).

This hint, while well intentioned, is a pretty desperate fix if you ask me. There has to be a better way (and it would just be best if Apple fixed thius once and for all).

I've tried using Appletalk, sharing the printer in Classic, and trying to use it from OS X (which can act as an Appletalk printer client), but to no avail.

Yes, this is a workaround and not a real fix but that is the best we will ever get. There is no motivation from apple to add more OS X drivers since people will already have to migrate to X and a big chunk of their prime market use postscript printers. The printer manufacturers have zero motivation since they are in the business of selling NEW printers. The only way around this is to get a community with some experienced coders to teach us how to write our own drivers.