Ratty, if you have the money, and its the film you've been looking for, go for it. I will do the same if (heaven forbid) Velvia RVP 50 is discontinued in 120. There are some films which look soo great from a personal perspective that stocking them up in case of discontinuation is a valid option.
I have about 40 rolls of E100G in the freezer and the only reason why I did not increase the stock further is that Provia, while not a direct substitute, is a valid option which needs to be bought and used on a regular base to prevent it from being dicontinued as well. But Velvia has no substitute.
I'm going there Sunday, and bringing a VERY large bag with me.