Thank God I'm not the only one! I'm on host13 as well and have been noticing some huge spikes in my load at weird times.
I have a Linode 128, and it seems pretty responsive most of the time. My io_rate rarely goes over the 200 refill rate, and my linode has a pretty consistent load average of about 0.4 with spikes when I do package installs to a little over 1.0.
I've begun noticing that at about 7:45am CST every morning there's a HUGE load spike on my Linode & all of my stats that update every minute fail completely. By the time my stats logging comes back on the first value it records for load is over 20! So I'm guessing that means that it peaked well above that even!
I started another forum about this issue a few days ago
here. I'll continue watching this forum for more discussion on the issue.
(By the way, it can't be my Linode's fault: my Linode has only consumed 3% of 1 one host cpu for the month!)