Still unsure what type, but I am almost positive its a sawfly larvae. This image looks similar:
http://tbn0.google.com/images?q=tbn:xzR ... 00060G.jpg
Here is how to tell difference between caterpillar and sawfly larvae:
The larvae look like caterpillars (the larvae of moths and butterflies), with two notable exceptions; (1) they have five or more prolegs on the abdomen (caterpillars have five or fewer), and (2) they have two ocelli instead of the caterpillar's six.
Typical sawfly larvae are herbivorous, the group feeding on a wide range of plants. Individual species, however, are often quite specific in their choice of plants used for food. The larvae of various species exhibit leaf-mining, leaf "rolling", or gall formation. Three families are strictly xylophagous, and called "wood wasps", and one family is parasitic. The larvae that do not feed externally on plants are grub-like, without prolegs.
Hope that helps. I nearly sure I have one of those I took a pic of as well, and I was told by Ian Kimbler (UK Moths) it was a sawfly larvae.