I think a big VPS will do your job, what you'll need is nicely optimised apache, php and mysql. I'll suggest use of lighttpd and xCache plugin of wordpress which will increase your site speed and accelerate them at good rate. We can give you a great VPS with LxAdmin and Lighttpd configured at its best or of course cPanel VPS Optimized is always another choice... 15 day money back guarantee is always there if you don't like being with us but probability of that is really low .
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