I have to ask why there are no signed binaries of the Bitcoin Clients? The bitcoin client is the center of what should be a very secure system for an individual. (Unless their primary accounts are on MtGox or a similar site, in which case they have to trust ssl and MtGox.)
On Windows the binary has no digital signature on the executable. Other less important software has digital signatures (media players, games, even poker clients are signed (PartyPoker is signed with a Thawte verified certificate).
On linux, there are no hashes available of the current distribution .tar.gz. Ubuntu offers hashes of their product through a ssl encrypted page:
https://help.ubuntu.com/community/UbuntuHashesPGP signatures for communication with bitcoin developers are readily available on the bitcoin.org front page next to their email addresses. Why aren't there verifiable gpg signatures for the binary downloads also available?
Good question! I'd imagine it's because the developers are overworked and underpaid!
I'm not sure how practical digital signatures would be in the short term, as Thawte etc will charge for them - but hopefully someone nearer the issue than me can comment.
Regarding hashes, that should be pretty easy to implement - but I'd imagine it's time that's the problem. I don't suppose you'd be able to volunteer to help out the devs with this?