Thunderbolt is too new to have decent cheap open source cable/accessories available, but too old (and not popular enough when new) to have many actually useful

Thunderbolt is too new to have decent cheap open source cable/accessories available, but too old (and not popular enough when new) to have many actually useful cheap used accessories. A lot of those old Macs would make decent little random servers if you could attach faster storage or networking without spending a ton.