I find it a real faff pricking out tiddly seedlings like Lobelia. I believe when I have bought some in the past that they were "clumps" of seedlings, so that is probably how the commercial boys do it too. At the time it annoyed me as I was buying the White flowering Lobellia, which always contain a few Blue ones. I grow mine singly, take them to flowering size and chuck the odd blue one before planting, but the clumps I bought yielded at least one blue per clump and it wasn't until long after they were planted out that the flowers showed, and was then tricky to pull just the Blue ones out :(
I might have a go at clumps though for things that have very fine seed though. I too have some of those miniscule-cell module trays and they will be just the job.