I'm not really sure if I understand what you are trying to accomplish. But if you are just looking for a server with the capability of sending 10000 emails at once, any mail company with a dedicated server can take care of that for you...
However if you are looking for the actual addresses you can run into trouble on several fronts...The biggest is that there are a ton of services on the web that will sell and send that amount of addresses for you. However most of the time the large majority of the addresses are old and/or not valid anymore..Second they will often times sell you email addresses that are not targeted to your market target...In other words the address might have been collected from someone who is interested in buying pots and pans and you are trying to sell sporting goods....
Another thing you need to consider is that they may sell you a bunch of addresses that are not 'optin' addresses..This means that if you send mail to addresses that are not opt-in addresses, it will be considered spamming...Just a couple of complaints to the ISP and they will shut down your service..
(An opt-in address is an address that has given you permission to send them information and offers).
One thing also to keep in mind is that you need opt-in addresses that are highly targeted to your market target. The reason for this is that most of the time you will only get about a 1 1/2 to 2 percent conversion rate from your mailing and you don't want to be paying for sending a bunch of mails that are not even going to someone who might be interested in your offer or product...In other words it would be a waste of money and time to send an offer for a deluxe bicycle to a stock car driver.....