12V hard drives are going to be a bear to get working with the webpal, the internals only provide 5V which is why laptop hard drives are such a good match. Here's a link to another post about regular hard drives on the webpal, where a reply gives a _possible_ way to get 12V, but doesn't rate the chances of success as very high.
http://www.linux-hacker.net/cgi-bin/UltraBoard/UltraBoard.pl?Action=ShowPost&Board=wpalgen&Post=80&Idle=0&Sort=0&Order=Descend&Page=1&Session=
NIC's have been a more difficult issue. The only ones I know of that have been reported to work with the webpal with no hardware tweaks required (it's still not an 'out of the box' install) are some generic 10Mbps ISA cards that were stocked at Halted in Santa Rosa, California. Scrappylaptop put a post about him picking up the last of these cards so he could pass them on to other Webpal users. I believe his post is in the for sale/for trade forum. He was extremely helpful when he sold me one of them in November, and it sounded like he had a few more on hand.
Other NIC's have had very poor results. Someone will occasionally report they found one that works (I think Vit_sfba had one) but they usually require hardware modifications, and their results have not been reproduced with other cards of the same brand/chipset (there may be minor hardware differences between versions &c that made others' attempts fail). Bigbrd has posted a number of times on how incomplete the Webpal's ISA implementation is, and why this is particularly a problem for network cards.
