There is a similar facility at geotribes.es, however it does not dynamically get the logs, so each time you visit it goes off to collect the updates. I have a lot of trackables, some have travelled a lot of hops, so when it gets my updates the browser times out. For me it gets all the data after two or three retries.
The advantage of geotribes.es over geocaching.com is that all your trackables current locations are on one zoomable google map with its current status (in a cache, carried, unknown, etc), and selecting one shows its travels. This part is implemented very nicely, however it does not cope with my personal TB which I carry around and has visited every cache I have been to but never sat in one. (My TB works on Geocaching's map, although that takes ages to load too.)
I imagine that for Project-gc to start tracking TBs would be a major piece of work. They would do a better job than geotribes simply because of the automated daily update. I would love it to happen, but I am not expecting it. Ever. In the meantime, check out Geotribes.