I see real great comments and feedbacks in here. I really apppreciate that.
Althought I still know nothing about other's experience with those "re-eningeered" designs, I see an interesting point here. Would any decent implementation of those "re-engineered" designs amount to anything?
If you happen to look at those listings in eBay, you'd see the parts are actually not so bad. Of course, like Kw6 said, the quality transformers could not be reproduced in those budget-minded imitations. So it's expected to be (several) cuts below the real thing, but could it compare favorably with, say, any decent $2000 preamps out there, simply because it's still fundamentally a great design?