I might sound like a douche when i say this but i just have to. Did you really design your game around a feature you are not sure about how to do? That seems kind of short sighted.
Oh boy, this is something I tried a few eon's ago, and let tell you this, unless you can get a programmer that know Unreal-Script, and a VERY good material/shader artist, and they both work together, ONLY at that point can you achieve what you're asking for through particles.
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Anyhow, instead of critisizing im going to try to be helpful.
Im pretty sure i saw something about this in Valves many publications.
http://www.valvesoftware.com/publications/2011/gdc_2011_grimes_nonstandard_textures.pdf
Im guessing you are after something like this.