the Supravox looks great but like the php might be out of my price range for a DIY projectThe standard Supra 215 used to sell for around $200.
You might also consider a Visaton B200 which is much cheaper.
One point with such drivers, is they favour high frequency over low frequency reproduction; you're better off cutting seeing these as "wide-range" drivers to be assisted by a woof (and, preferably a tweet too).