OK well, for the last few years I have had my eye on MediaTemple's grid offering, after testing I just ain't satisfied.
I require a shared US host that will not suspend when spikes in traffic occur.
MediaTemple do boast the following which they no doubt stick too.
No site should be penalized just for getting popular. If you find yourself in the spotlight — like hitting the front page of Reddit, or blowing up on Twitter — your web host should be able to keep up. The Grid’s bandwidth scales with your traffic. So you can grow without worrying about getting shut down.
Does anyone else in the industry offer something similar? Cost would not be an issue however I would not like a VPS at this stage.
I see you mentioned you don't want to look at VPS at this time, but if you are worried about getting suspended on shared hosting due to traffic spikes, it may be time to look at cloud servers or VPS. On shared hosting you are sharing server recourse with other customers. If your site gets a traffic spike and it starts affecting the performance of the server, your service will get suspended.
Rackspace has very good cloud servers. I haven't used their cloud sites, but from what I'm looking at cloud sites may be what you are looking for. Of course their prices are on the higher end, but you do get what you pay for.
I've used a number of services attempting to provide the clustered/grid format that Media Temple and Rackspace have attempted, but in all cases I've never been impressed by the performance.
I believe that the reason for this is that when it comes to raw performance, you just can't beat having a single machine (or VPS segment of a machine) with a hard drive connected directly to it that stores the database, etc. Services like Media Temple's do indeed allow for huge amounts of seamless scaling, but that's because they effectively split everything up into separate machines/SANs that communicate with each other via network. Your files, database, and web server could all be on different machines, and all of them are typically sharing a lot of different clients. Also, using so many different machines can pose serious problems when it comes to caching PHP and database requests, making things even slower.
If I were you, I'd forget about the great-on-paper 'can scale to support any traffic surge' requirement and just get a rock solid managed VPS. To put into perspective just how efficient a well-engineered VPS can be, I can literally throw 5000 requests per second at a 1GB Linode VPS using Nginx instead of Apache and the CPU/RAM/latency is virtually untouched. With dynamic pages it wouldn't be so high, but we're still talking the ability to cope with massive amounts of traffic. And if you do outgrow what one VPS can offer, you can load balance or network them and create your own 'mini grid'. I've experienced Reddit a number of times and not once has it been enough to hurt my 1GB VPS — and that's with a mostly uncached IP.Board forum.
To put it simply — and this is based upon many years of trying a lot of web hosts — shared hosting, large amounts of traffic, and high performance just don't go together. At the price point where it does become feasible, you'd be much better off either getting a managed VPS from somewhere like Future Hosting (not expensive and they will configure it exactly as you wish) or learning how to manage a Linode.
They also had a day of DDos(I sympathise with them here) and then a few days of ongoing abusive clients.
Yes, DDoS is not what it used to be... available to the "elite" only. Today, 5 bucks will buy 6-7Gbps of UDP traffic for an hour and that could bring a host's shared structure to a halt. One would think that hosts should do something about it in the way of DDoS mitigation. And, indeed, we see more and more of them offer (or claim to) mitigation.
You mentioned traffic spikes. Now, are these generated naturally, or are you referring to DDoS attacks?