Just how long of SATA data cables do you need? Three foot SATA data cables aren't that hard to find. SAS to SATA breakout cables 1 meter or longer aren't hard to find either. Unless you are running a real monster, I can't see needing anything longer than 36". Push come to shove, you could extend your SATA data cables by joining two with one of these
Since you are essentially adding two connections to the line, you might suffer some signal loss or corruption from one of these.
Edit: After doing a bit of research, there is a 1 metre (roughly 39") limit on the length of a SATA data cable. Check here
under Data Connector for more on that.
Power cables—SATA power, MOBO cables, PCIE 6 & 8 pin cables, etc.—and other cables, such as audio and USB, can be made up yourself. All you need is some appropriately sized wire (the longer the run, the larger the wire should be to avoid voltage drop), sleeving, heat shrinks, connector bodies, pins, and a crimper. I made up all the modular PSU cables for the build I'm working on. Making your own cables will result in a cleaner look since all of them will look the same and will be exactly the correct length. It could also improve airflow in the case. I would avoid adding too many extensions because of added resistance from the extra connectors in the run and because the longer run will cause even more additional resistance because wire size hasn't been increased, resulting in more voltage drop or signal loss. C2G
carry a good selection of SATA data cables up to 1 metre. Performance-PCs also carries connectors, pins, crimpers, wire, sleeving and shrinks for making up your own power cables.