Originally Posted by troyz
You can try using dcraw version 8.86 or higher to generate an 8-bit TIFF file directly;
dcraw -v -T -w rawfile
Yep, I can convert the DNG/PEF files just fine using the dcraw and netpbm CLI as I mentioned above to either TIFF or JPEG, which is why I'm a little puzzled on why the other tools don't work as a good many of them use dcraw and all the versions of dcraw from 8.77 and up I have tried work just fine.
If I can get the ufraw CVS version downloaded and compiled that may clear up things for DigiKam, f-stop and rawtherapee as I believe they all use the ufraw backend. LightZone is my tool of choice but I'm not going to hold my breath on them getting out a patch any time this century *grrrr*.
Thanks to all that have posted replies. If I find a magic bullet for this I'll be sure to pass it along.