Selling copies of blockchain database on disc Is it ethical / legal / at all possible to burn a copy of the Bitcoin (or any cryptocurrency) blockchain to a disc, and then sell the disc? Would there be any additional issues if we included a copy of the client (and associated source code)?

The idea is to make it easy for people to get started using Bitcoin without having to download 6 or more years' worth of blockchain data. The content would essentially be the Bitcoin data directory (minus the wallet.dat of course), and, if possible, the client. Users could insert the disc, install the client, and have the entire blockchain as of the date the disc was published.

Is this legal under the terms of the MIT license? Is there another license covering the blockchain data itself? Would anyone actually be interested in something like this?

I was thinking that perhaps something like this could be published annually, with the profits going to support the Bitcoin developers.
Is this legal under the terms of the GPL?

Bitcoin Core is distributed under the MIT license which explicitly allows this.

The content would essentially be the Bitcoin data directory (minus the wallet.dat of course), and, if possible, the client. Users could insert the CD, install the client, and have the entire blockchain as of the date the CD was published.

This is not recommended. Beyond modifications to the software (which can be caught with signatures) distributing a raw synchronized database is very vulnerable to tampering. The unspent outputs database can be silently modified to include non-existing outputs which the user would be likely to discover until it is too late. With knowledge of the people running a corrupted database an attacker can fork those users off the network very at their leisure, or if they accept zero confirmation transactions the victim can be directly defrauded at nearly no cost.
When a bootstrap.dat was distributed as a faster way for users to sync with the network it was always completely verified to avoid this type of attack.

Users could insert the CD, install the client, and have the entire blockchain as of the date the CD was published.

From a feasibility perspective this would actually be 60 CDs, or 7 DVDs at the time of writing.