Great project, I love bringing old stuff back to life! For the 478, you can aim for a Pentium 4 HT at 3.4 GHz, 2 GB DDR max. For the 775, a Core 2 Duo E6700 goes well, 4 GB DDR2 in 2x2 GB. Both manage 2.5" SATA SSDs, but the performance will be limited by the bus. The drivers can still be found...