Thanks! Yeah I saw 8ft to 25ft for sale and I've ordered a couple of 10 footers for my use. It just made me curious as to what any length limits there actually were.Yes, there are - but if 6ft are just slightly too short for you, it's not going to be a problem - just pick up some 10ft (or 8ft etc, depending on price) and be done.
IIRC, both HDMI 1.4+ and DP1.2+ are ~50Ft max, and you'll see some degredation depending on cable quality below that, but <25Ft and there shouldn't be any concerns whatsoever.