Well... 36x16* is the gear I used for the one cyclocross race I've done to date.
I had a few comments at the start of yesterday's race - eg "That's a brave choice" - but there weren't many places where I missed having a wider selection of gears. In fact, the gearing was pretty much spot on for that circuit, and if anything, I missed having higher gears more, as they would have been useful on the flat, fast sections of the circuit. Also, singlespeed means you have fewer things to go wrong on the bike, your bike is lighter overall, and you never risk being in the wrong gear (I passed a few people who were struggling with gear changes).
In a race, I reckon having lower gears at your disposal is a mixed blessing - if you have lower gears, you use them; if you don't have them, you're forced to push that bit harder up the banks. As others have said, your ability to get up the steep bits is more about you than the bike. There were places on yesterday's race where I was riding up steep banks that others with multi-geared bikes were getting off and carrying it up.
The
only way to get good at riding up steep hills is to practise riding up steep hills.
d.
*that's about a 61" gear on 34C cross tyres.