I've checked out Amazon EC2, RackSpace, And Linode, They're great actually but each has its pros and cons.
EC2 offers 5 IP's already without request, but it's impossible to associate multiple IP's to one instance.
Rackspace And Linode are a bit greedy and offering 1 IP until request, I know that they hardly get IPV4, But i've dealt with many vps providers that don't limit them that much.
So i'd like to try out any reliable vps providers that aren't new to business, have very little downtime, and offer a fair amount of IP addresses without telling you how to run your business.
My current provider has all that but the downtime part, my vps gets down several hours weekly.
Those are all excellent web hosts that you have mentioned, and arguably some industry leaders, particularly Rackspace. Sounds like your host has some nice bells and whistles but lacks the expertise of any good web host: exceptional uptime and support.
http://www.rackspace.com/cloud/cloud_hosting_faq/#cloudservers They offer additional IPs for only $2/mo. From my own experience I have hardly found a better deal with such a reliable, industry-standard web host. A basic cloud server there is $11/mo, and if you wanted even 10 more IP addresses, you'd only be pushing $30/mo which is a remarkably good price for cloud computing with 10+ IPs.
(For the record, IPv4 addresses are becoming scarce and IPv6 isn't fully adopted yet, so other hosts such as MediaTemple, who provides extra IPs for only $1/mo, want to make sure you have a good reason to order them. But if you have a truly good reason for needing more IPs, I'm sure that they'd be happy with the sale.)