Know of any C-ISAM Clones/Substitutes?

Does anyone know of robust, commercial ISAM packages for UNIX? A direct Informix C-ISAM clone would be nice, but an ISAM package that supported similar functionality would be acceptable. Requirements: Must run on SunOS, IBM AIX, DEC Ultrix, and HP U/X. Must be VERY reliable. Source code is NOT required. Prefer commercial package with no run-time fees or alternatively has a reasonable royalty buyout option. We have tried D-ISAM and found the vendor too unresponsive when we had problems. We find Informix's current licensing policies too restrictive and the company too glacial-like in their negotiations. BTW, if anyone has a buyout agreement for C-ISAM or prepaid blocks of C-ISAM licenses with Informix that are assignable to a third party (I know this is a long shot), perhaps as part of an asset sale, call me. If the license can be transferred legally, I MAY be interested if the legal part doesn't look too difficult. [Discontinued or obsolete product lines, nearly bankrupt companies, may have this asset on their balance sheet, etc] Please contact me at +1 408 748 8649 ext 204 or via e-mail: paul@aim.com.