Once a single transaction in pruned in a block, the block is no longer eligible to be served to other nodes. 
Which transactions are pruned can be rather custom e.g. even depending on the wallet(s) of the node,
therefore I guess it is more handy to return some bitmap of pruned/full blocks than ranges.

Tamas Blummer
http://bitsofproof.com

On 07.04.2014, at 20:49, Gregory Maxwell <gmaxwell@gmail.com> wrote:

On Mon, Apr 7, 2014 at 11:35 AM, Tamas Blummer <tamas@bitsofproof.com> wrote:
BTW, did we already agree on the service bits for an archive node?

I'm still very concerned that a binary archive bit will cause extreme
load hot-spotting and the kind of binary "Use lots of resources YES or
NO" I think we're currently suffering some from, but at that point
enshrined in the protocol.

It would be much better to extend the addr messages so that nodes can
indicate a range or two of blocks that they're serving, so that all
nodes can contribute fractionally according to their means. E.g. if
you want to offer up 8 GB of distributed storage and contribute to the
availability of the blockchain,  without having to swollow the whole
20, 30, 40 ... gigabyte pill.

Already we need that kind of distributed storage for the most recent
blocks to prevent extreme bandwidth load on archives, so extending it
to arbitrary ranges is only more complicated because there is
currently no room to signal it.