dont forget, most of the scsi items are not even consumer products so chances you'll find microtech etc at your local pc farmer are slim (hence a pcd47 cost about $400 new).
The ide can be used for a HD, but i personaly prefer solid state because the one cool thing about having a cardreader in the first place is to get rid of noise in your studio, so i follow that. Downside is that the older format are larger but also cheaper to aquire, but the newer ones are as small as an ide male socket with the ram modules directly on top (as pic posted earlier). The lastest and largest format to date is 856Gb (SSD) of which i have not found a pricetag but is obviously to much for sample storage (A-Z x 1GB, 26Gb = 30Gb < wasted).
Here are some small ide format ssd's ranging from 128mb (42 euro) to 4Gb (232 euro)
http://www.altec-cs.com/web/h_en/prod/a ... /index.htm
somewhat cheaper but a bit bigger, an ide flash modules from Transcend with dimensions 59mm x 27,3mm x 7,3mm a bit bigger and could possibly be in the way of the scsi socket/connections but could easily be solved by adding a ide cable to a clear space inside the mpc. These are cheaper but in general, the highest storage found is 40 pin 8Gb (a 151 euro)
http://shop.transcend.nl/product/produc ... indexnum=4