not the answer you were looking for, but i love this yeast great all rounder.
i used it with an esb fresh wort amber ale, it turned out great. if anyone is looking for quick and easy beer this is great.
make it to 19L though.
Can't find what the exact whitelabs strain equivalant is ATM or even if there is one.
HBA sell the JPA ingredients as a kit with everything you need and packed that with wlp002 but reading the specs on 002 i think it would finish a bit to high as is with most yeast you'll finish these beers around 1.018-21 or so anyway so you would'nt what a low attenuating yeast or you'll be up around 1.025.
Reading through the JPA thread a little again and looking at a white labs chart it looks like wlp005 would be the closest you could get to the wyeast 1026.
Saying this though i don't think its is the same strain or anything though.
If you really do want cask ale yeast dave at goliaths has the big activator packs of it for $17. I know a bit pricey but believe me its worth every cent.
Anyway it does look like some of the hard core brewers on HBA are recomending using wlp005 if you can't get wyeast 1026 for the JPA.
Anyway i would go straight to the goliaths online brewshop and put your order in for a pack of cask ale. B)
I have done almost all my favourite ale recipes with the 1026 and they all have come up really really good, actually better than really good, they have come up exactly how i like them.