You can use /scripts/wwwacct to create accounts via commandline:
[email protected] [~]# /scripts/wwwacct
Please use the this syntax
wwwacct <domain> <user> <pass> <quota> <cpmod[advanced/?]> <ip[y/n]> <cgi[y/n]> <frontpage[y/n]> <maxftp> <maxsql> <maxpop> <maxlst> <maxsub> <bwlimit> <hasshell[y]/[n]> <owner> <plan> <maxpark> <maxaddon> <featurelist> <contactemail> <use_registered_nameservers> <language>
The owner flag will set the account ownership so something like:
/scripts/wwwacct joetest.com joe joessupersecretpassword 1000M x3 n y n 99 99 99 99 99 0 y RESELLERUSERNAME
should work and you can bash script it from there. As for the DNS aspect of your issue, you can try using the DNS templates to set the A entry to the remote IP. I think that might work.
Edit Zone Templates