Use a pseudo random number, not follow bad examples. Where are these examples? I'd be curious as to what they say regarding why they haven't followed the pseudo random number requirement.
Use something like fd00::1234, or incorporate something like the interface's MAC address into the address? It'd make the address quite unreadable though.
Unique Local IPv6 Unicast Addresses http://tools.ietf.org/rfc/rfc4193.txt
[snipped a bunch of stuff above]. According to the RFC: 3.2 The local assignments are self-generated and do not need any central coordination or assignment, but have an extremely high probability of being unique. 3.2.1. Locally Assigned Global IDs Locally assigned Global IDs MUST be generated with a pseudo-random algorithm consistent with [RANDOM]. Section 3.2.2 describes a suggested algorithm. It is important that all sites generating Global IDs use a functionally similar algorithm to ensure there is a high probability of uniqueness. The use of a pseudo-random algorithm to generate Global IDs in the locally assigned prefix gives an assurance that any network numbered using such a prefix is highly unlikely to have that address space clash with any other network that has another locally assigned prefix allocated to it. This is a particularly useful property when considering a number of scenarios including networks that merge, overlapping VPN address space, or hosts mobile between such networks. ---- Global ID in this case means the 40 bit pseudo random thing. The point here is, we are all supposed to pick our own poison and pray that we are unique. Though an algorithm is suggested in 3.2.2. Perhaps SIXXS uses it. Anyway, the SIXXS tool seems pretty slick. Deepak