24/2 and Delta 3200 should solve any speed worries you ever had, and will be usable on a greater variety of bodies. Don't forget about the 28/1.8 (both AF-S and AF-D models).
If the conditions you are shooting in are too dim for f/2 and 400, then going up to Delta 3200 is going to be far more helpful than scrambling for an extra f/stop.
Personally I shoot a 35/1.4 Ai-S with D3200 in my F3s and F4, and a 50/2 Summicron on my Leica with either pushed HP5/Tri-X, or D3200. It's really not -that- much grainier than a 400, and it's a very nice pattern.