The CPU limit is not as much of an issue as it may seem. If your business site consists of mostly static or cached pages then you are unlikely to run into the limit, even with the traffic figures that you mentioned. 100k hits per month does sound like a lot, but it averages out to one visitor every 26 seconds or so. Obviously, there will be times when the traffic is greater than the average, but overall it is not likely to tax the CPU too greatly, unless your site contains a lot of dynamic content and the scripts generating this content are CPU intensive.
More information on CPU minutes can be found in the wiki article linked below;
Unfortunately, in a shared hosting environment, some sort of resource limits are inevitable. I think DreamHost is being more honest than most by making the limits known.
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