Well, according to BeerAdvocate (if you believe their reliability) a session beer is 5% or less ABV and the Brewers Association defines it as 4.0 to 5.1% ABV (which pretty much takes it out of the IPA category.) What you are describing and looking for would be a nice malty Pale Ale. For me, the nice part about IPA's is the malt that has to balance the high level of hops. Pale Ales are actually a little more balanced towards hops, so if you reduce a Pale Ale hops a bit, you should get a nice session ale. Especially with some nice dry hopping.