I don't know if this is still relevant to you anymore, but it would probably be useful for people doing searches:
I've been looking around ebay for a while, and noticed that buying just parts for TC1000/TC1100 can be somewhat expensive. I've seen pens alone go for anywhere between $9 and $29 USD. Motherboards and digitzers can easily go for $80 individually too.
Considering you can get the entire machine for around $140 to $220 in working condition, your best bet is to just buy another TC1000 and use it for spare parts.
Keep the rest of the parts in storage for what ever may go wrong, or re-circulate the parts back into the market for other enthusiasts to use. I see lots of sellers on ebay selling a TC1100 in full working order, minus the hard drive, or without a working screen, for around $100. Thats a good deal for a fully working PC minus one or two parts!
I recently purchased another TC1100 so I could replace the motherboard in mine. I might recirculate the rest of the machine for anyone on ebay looking for a digitizer, pen, keyboard, or whatever they may need. The second hand market for this device is great. Since all of these tablet essentially use the same parts with each other, its not hard to replace worn or broken parts at all.