Ah I'm doing the exact same thing as soon as my basement office is finished ! Got my pimped out 1200 but nothing beats my A1000 with 40mb external scsi HD & original Amiga monitor :-)
First thing you gotta get is one of kippers 4 or 8mb internal fast ram boards here:
http://kipper2k.com/amigaforsale/Quality stuff always from kipper so buy with confidence.
If you want to join in on the group buy for a new GBA1000 board just join in on the thread over here.
