Yes, you could get 24/38 on shimano too.
My reasoning is that on a 36T front and a 29er, I found i was staying in the outer for most riding and used the inner for steep climbs and as a bailout. 38 would be just that bit taller and would see me changing the front more often. I never seem to run out of gear at the top end so 36-11 vs 38-11 is no benefit.
FWIW, I have 26/38 on my 26er but the difference in wheel size means they are actually pretty similar. And in any case my 29er is a single front set up now (30, halfway between 24 and 36, although did have a 32T for some time and that was OK too)