I tried using the plastic alphabets provided by Slater's Plastikards tonight, and I think the result can be quite nice with a bit of practice.
I think I'll have to recommend using the 3mm letters over the 2mm ones I ordered for my Snotlings. I am definatly getting such for my Ogres, and probably for my other teams as well. The 2mm version was just a tiny bit to small to be easily handled, but fit right nicely on the 20mm wide bases, even though I did some of the letter a bit crooked.
Here is a preview.