Well that hopville link is also my recipe.
I love this beer. I've brewed it three times with slight variations on the theme. Standard chocolate malt is best, and closest to the Founder's recipe. I just subbed the Crystal out of necessity that first batch, and it wasn't a significant flavor impact. For yeast I think that WLP001 Cal Ale gets closest to a clone, but I really like the WLP002 English ale character with it too.
I can tell you that I also e-mailed the brewer, and I actually took my percentages from his response. The exact malts weren't specified to the color or supplier, but he gave me a lot to work with.
Let me know how it turns out. This one is in my regular home rotation now.