URI way-back machine

Hi, I have an idea for an interesting web service (sort of)...
We all know every URI stops working as expected one sad day and we want
to get the functionality they offered at some point in past.
This is a way to connect REST applications with web archives/caches.

Somebody would provide a domain which would serve for the purpose of
representing URIs of other domains at some point in time. This should be
someone reputable who will not want to use the domain later for other
purposes and can offer the longest ownership of it (purl.org?).

For example URI: http://time.purl.org/iso8601/2008-08-29/http/purl.org
(http://time.purl.org/[timeFunction]/[timeFunctionArgument]/[schema]/[theRestOfTheURI])
would translate into: http://purl.org on day 2008-08-29

This translating and attempt to fetch the data from past would be done
by the client applications, the web service on time.purl.org would just
redirect clients who are unaware of the mechanism to the translated URI
so even though they did not get the desired content from the past, they
still try to get what is at the URI in present.

The use of time function would enable various formats of time and
choosing methods, or even an argument-less function for getting list of
all version the mechanism is able to fetch. In fact this can be used not
only for retrieval of content from past, but any actions which require
the wrapped URI to work as normal when the mechanism is not supported.

Of course the web service could provide the mechanism too so no change
is needed in the client applications (but applications could override
it), but this would limit the choice of time functions to those provided
by the service, though some standardization would be good.

I know it's a hack but useful one IMHO.
What do you think?

Best regards,
Jiri Prochazka