In fact, there's quite a few Linux drivers that support Poulsbo & Co, but unfortunately all of them are in a pretty sad state and ill-maintained. Bug 2205 with the MeeGo Project is interesting and it's about integrating the EMGD driver into this Nokia-Intel Linux OS, but as we found out yesterday, that's not happening in its current form.
A MeeGo user (who is also a Phoronix user) had asked "Just how many different drivers are there intended for the same chip (being powervr sgx 535)?" The response from Intel? Joel Clark of Intel who made yesterday's talked about comments and was working on the bug in question, simply responded with "too many."
Now if Intel could just get one driver for this hardware on Linux that's well maintained. They may not be able to fully open-source the driver due to their IP licensing deal with Imagination Technologies, but they could at least do more than keep introducing new half-baked drivers.