I was thinking about using layer maps with form, but the scattering tends to be a bit too much, or very little on those. Maybe exporting some objs from cinema to fill? How do i go around telling form or particular to taper off the production of particles at the edges? Maybe element3d could be of help here?
particular allows you to use a layer as an emitter. it determines where the particles will emit from based on the alpha of the layer (opaque areas emit particles, transparent areas don't).
so for your example, you could use couch shaped layer to emit a custom particle that is the word 'bla', and it might get you close.
having 2 (or more) particle systems with different layer emitters would allow you to have different particle behaviors... so if you were to use simple choker on one of the layer emitters to change alpha area, you could change the birthrate (or speed, size, etc) of those particles and layer that with the other particle system(s) to get the look you are after....