You're not going to find a "swamp" address with any ease.
You need a globally routable addy and in /24 these are few
and far between. (We used to call up the NIC and say "hey
my mail server needs another 30 addresses, can I have a C
outta 204)
You really have 2 choices;
Talk to your current provider, most will give you more addresses
at a small price.
Join ARIN (
www.arin.net ) and apply for a globally routable /24.
Not exactly cheap and the paper work is a bitch, but once you've
got it and got it routed, your provider has less of a stangle hold
on you.