Re: Namecoin is Prime for a 51% attack
As was already mentioned on the bctalk thread, Merged Mining will start at block 19200. If a majority of the network upgrades by then, and if pools start offering merged mining, then we'd expect to see an increase in network speed.
Until then, the network speed may remain low and a 51% attack is a real possibility.
+1 for posting this, and requesting feedback prior to launching. I'm sure others will have comments and answers to your questions.
Might also want to consider using namecoin-testnet first.
(and for those new to the 51% attack, see: http://bitcoin.stackexchange.com/questi ... wer-do/662