I looked in the archives, and find this was being worked on almost 3
years ago, and indeed, this version claims it has largefile support:

curl 7.13.1 (powerpc-apple-darwin8.0) libcurl/7.13.1 OpenSSL/0.9.7i
zlib/1.2.3
Protocols: ftp gopher telnet dict ldap http file https ftps
Features: IPv6 Largefile NTLM SSL libz

Nevertheless, I just tried to use it to download a 4.3G (4.6 depending
on how you count it) file, but curl thought it was 335M and stopped there...

-- 
Alan Batie