You should stick the Xindak FS-01 and FS-02 in addition to the Supra Sword speaker cables to demo. Each of these is below the $1k price point for 2M (except the FS-02 which is a bit more than $1k). In terms of sheer value each of these cables are very tough to beat.
Personally, I think you would be spinning your wheels spending upwards of $4k-$5k on speaker cables. It has been my experience at the end of the day, in a system that is truly reference in every component, cable, and cord, speaker cables make the LEAST amount of difference. A reference system can sound still absolutely amazing with speaker cable that is not quite up to par with other reference gear. Try sticking a sub-standard AC cord in a reference system, sound can go straight to hell in a handbasket.
Before spending $4k-5k on speaker cables, I would look at getting a seperate DAC. The Capitole is a great one box player, but getting the right DAC in your system (for say $2k-5k) would totally blow the Capitole away. It would be a much bigger gain in digital sound quality than moving from say even the Xindak FS-01 speaker cable to the Jena Pathfinder in your current system.
Remember, if the information (in the signal) is not there once it gets to the speaker cable, no matter how good of speaker cable it is, it is not going to add that information and make it better.