This scenario is the exact reason email auth exists. I understand you may not be fond of it. However, that is it's purpose. In the original spirit of NickServ, it is so users can register freely without having to rely on IRCop intervention to reserve their nick. This is why the current process is in place.
Reference registration throttling, It's already in place since sometime in 1.7.x
# NickRegDelay <seconds> [OPTIONAL]
# Prevents users from regging their nick if they are not
# connected for at least X seconds.
#NickRegDelay 30
There is also another delay between registrations.
You can also delay the /ns RESEND command:
# NSResendDelay <time> [RECOMMENDED]
# Sets the minimum length of time between consecutive uses of the
# RESEND command. If not given, this restriction is disabled (note
# that this allows "resend flooding" or "mail bombing").
NSResendDelay 90s
Combined with limiting users to a certain number of nicks per email via (This only works if you require an email address to register):
# NSEmailMax [OPTIONAL]
# Module: ns_maxemail
#
# Limit the amount of registrations with the same email address to the
# amount given here. If set to 0 or left commented, there will be no limit
# enforced when registering new accounts or using /msg NickServ SET EMAIL.
#
#NSEmailMax 1
Now for those that have already registered on your network you can do a mass drop by referencing the email address used, that is unless you disabled the email address requirement, in which case you basically opened registration up full tilt. The mass drop at:
http://modules.anope.org/index.php?page=view&id=87Additionaly you can make registration a 2 step process without using emailreg with a module found at:
http://modules.anope.org/index.php?page=view&id=78Now in reference to your request, it is certainly possible and I don't think one like it exists. I personally stick to nets that allow open registration, which is why I don't hang out on UnderNet and the like. Most users that come from NickServ style nets will agree and while I'm not telling you how to run your network, this is something you should consider very very carefully. The modules and features I've discussed here will cure your problem for sure without needing an IRCop to register your nick for you.
Please understand that in the end, it's your users that need to be happy with your network and thus their needs come before yours. If you want to require IRCop intervention and they do not, then you lose. If the burden of dropping spammer nicks increases, hire more staff but keep your loyal users happy or some other network will.
Hope that helps.