Hi,
My initial reaction was that it's something of a waste to hook two devices together like that, and thereby reduce some of the advantages that both would have individually. Combining them means that you end up with a heavy e-ink device and a relatively pokey little netbook. It looks like a sort of e-reader three legged race that would hobble both, for no necessarily obvious advantage.
Is building a Horsebicycle really better than having one of each? Is it because building an e-ink device that's more functional in its own right is not feasible yet? Are there enough people who really can't hack reading text on regular screens to want to pay for such a hybrid?
I'd guess that others might also be interested in an explanation of what you see as the point of hooking them together, rather than using two separate devices, or just one. For my money I'd rather see the same cost, weight and size spent on making one or the other more appealing and functional. If the netbook side of it worked well than I'd have no real need to cart round the e-ink side at the same time. But that's just me. However, I think that a lot of other potential buyers might also be interested in discovering the answers before shelling out the money.