Till, I do agree with you not all "custom page size" attributes in the foomatic generated PPDs are in the DRV generated PPDs.
This may be a issue but, your "lpr -P <perinter> -o PageSize=Custom.15x20cm <file>" command example does work OK with DRV generated PPDs.
For example the following command printed ok on FC9. Both old foomatic and new DRV PPDs gave the same results.
lpr -P psc750 -o PageSize=Custom.4x7in 4x7.ps
-dave
Till, I do agree with you not all "custom page size" attributes in the foomatic generated PPDs are in the DRV generated PPDs.
This may be a issue but, your "lpr -P <perinter> -o PageSize= Custom. 15x20cm <file>" command example does work OK with DRV generated PPDs.
For example the following command printed ok on FC9. Both old foomatic and new DRV PPDs gave the same results.
lpr -P psc750 -o PageSize= Custom. 4x7in 4x7.ps
-dave