Just thought I'd report back with my findings, as I went ahead and made what I call Apple Pale Ale.
I used a basic PA recipe as a base - I aimed for a 3 gallon batch. I simply topped up the 2 gallon difference with pure apple juice. Well not quite pure, it had some honey mixed in leftover from a previous experiment
Primary'd for 4 weeks using Safale S-04 (OG=1.052 FG=1.010). Then straight to bottle.
On bottling day I tried a sip - Not too impressed, very tart and thin. I was worried that the 2/5 proportion of AJ was too much.
Now 2 weeks later I'm pleasantly surprised. It's definitely an ale, with a slight but obvious odor/flavor of apple coming from it. The AJ gives it a slight tartyness which I don't usually like but it works quite well. You get a nice apple'ish aftertaste as well.
It kind of reminds me of the black velvets
we used to buy in bars.
I would definitely make this again. I was very impressed by the flavor and so were my friends!