64mb stack size limit?

[Joseph Gleason]

Short question:
Is there a way to increase the stack size limit for a user
process beyond 64mb?

Background:
FreeBSD in question is 5.2.1-RELEASE.

I am running an application (unison from
/usr/ports/net/unison).  This program by virtue to how it
was developed (or possibly the language is uses, that being
ocaml) uses a large amount of stack space when syncing large
directory structures.

With directory structures that contain on the order of
30,000 files, unison runs out of stack.

Using the bash shell:
ulimit reports a stack limit of 65536k:

# ulimit -a
core file size        (blocks, -c) unlimited
data seg size         (kbytes, -d) 524288
file size             (blocks, -f) unlimited
max locked memory     (kbytes, -l) unlimited
max memory size       (kbytes, -m) unlimited
open files                    (-n) 11095
pipe size          (512 bytes, -p) 1
stack size            (kbytes, -s) 65536
cpu time             (seconds, -t) unlimited
max user processes            (-u) 5547
virtual memory        (kbytes, -v) unlimited

Doing ulimit -s with a higher value does not seem to produce
an error or change to this value.

A little C++ program that I wrote to test stack limits
confirms the 64mb limit, regardless of what I tell ulimit.
Source is attached.
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